Despite recording its healthiest air quality ever, air near the Clairton Coke Works remains unhealthy, according to the latest American Lung Association [ALA] report. 

Allegheny County is one of only 13 counties nationwide that received an “F” grade for all three types of air pollution the group monitors for its annual air quality report: ozone and short- and long-term particulate matter.

But the ALA’s report, released Wednesday, is based on data from 2017 to 2019 and doesn’t take into account the record improvements in air quality across the county last year.

So is the air in Allegheny County unhealthy to breathe? 

The ALA’s answer to that question diverges this year from the answer you would get from the Environmental Protection Agency’s [EPA]. For the first time this year, Allegheny County’s air quality was in compliance with federal air quality standards at all of its sites. According to the EPA, which looks at air quality between 2018 and 2020, the county’s air quality was already healthy outside of the Mon Valley.

The ALA uses a single monitor in the Mon Valley to determine grades for the entire region because that’s where the air quality in the county is the worst.

The EPA standards aren’t protective of public health, said Kevin Stewart, the ALA’s director of environmental health. There were still 21 days where the air was considered unhealthy between 2017 and 2019, according to EPA data. For people with health problems, “one bad air day could be one bad air day too many,” Stewart said.

Jim Kelly, the deputy director of environmental health for the Allegheny County Health Department, said he is aware that the EPA’s current standards won’t protect everyone’s health and could be made more stringent soon. The health department has a number of initiatives underway to improve the local air quality, he said. 

Jim Kelly, Allegheny County’s deputy director of environmental health, listening to residents speak about air quality during a January 2020 Board of Health meeting. (Photo by Jay Manning/PublicSource)
Jim Kelly, Allegheny County’s deputy director of environmental health, listening to residents speak about air quality during a January 2020 Board of Health meeting. (Photo by Jay Manning/PublicSource)

The health department will begin informing Mon Valley residents when the weather could lead to unhealthy air and is proposing a rule that will force U.S. Steel to come up with a plan to reduce pollution during inversions. It’s also involved in several lawsuits with U.S. Steel over its coke oven regulations, its emissions at Edgar Thomson Steel Works and the fire at Clairton Coke Works in 2019.

The health department’s increased enforcement appeared to start paying off in 2019, as air pollution near the Clairton Coke Works started to fall. But the impact was nowhere near as large as the steps U.S. Steel took to decrease its production in 2020 during the pandemic and economic fallout. The air quality near the coke works in the Mon Valley improved faster than any other part of the county in 2020, according to air quality monitor data presented at an April air quality subcommittee meeting. 

The improvement was so dramatic that the air there wouldn’t even have been the most unhealthy spot in the county if compared to air quality data in 2019. It was still the most unhealthy spot in 2020 because all areas saw some level of improvement.

“If an area is getting straight Fs, an important question everyone needs to ask: Are we doing enough to move in the right direction faster?” Stewart said.

Mon Valley’s breath of fresher air

Air quality improved across Allegheny County between 2000 and 2013. Those improvements continued in most places across the county, except near the Clairton Coke Works in the Mon Valley, where the average amount of harmful particulate matter in the air actually increased for several years.

That story took a new turn in 2020. The air quality once again improved everywhere in the county, but it improved most dramatically near the Clairton Coke Works. The county already predicted that the air quality would come into compliance with the EPA’s air pollution standard there last year. But the improvement was more than twice as large as the health department’s rosiest projections before the pandemic. 

The air near the Clairton Coke Works in 2020 was about as clean as the air around Neville Island and North Braddock in 2019, and even cleaner than the air around Parkway East monitor in Wilkinsburg in 2019. The amount of harmful particulate in the air near the coke works in 2020 was about the same level as the typical air quality across the city of Pittsburgh around 2013.

Screenshot from the 2019 Allegheny County Health Department Air Quality Annual Report.

Why did the air quality improve so dramatically? The Clairton Coke Works had one of its batteries “offline or idle” for some portion of 2020, according to Kelly. That meant that 10% of the facility’s capacity and pollution wasn’t being emitted last year, he said. U.S. Steel said in a statement that none of its batteries were shut down in 2020.

The facility also voluntarily increased its coking times from 18 hours to more than 30 hours, which can decrease the amount of pollution released. The facility was previously required to increase coking times as repairs to pollution controls were made after a fire in 2019.

The air quality improvements were a yearly average and didn’t necessarily reflect the quality of the air every day. In fact, the air quality exceeded the EPA’s standard twice in November and once in December last year.

Air quality improved across Allegheny County in 2020 but the improvement was created at the Liberty monitor in the Mon Valley near the Clairton Coke Works, according to Allegheny County Health Department data. (Courtesy image)
Air quality improved across Allegheny County in 2020 but the improvement was greatest at the Liberty monitor in the Mon Valley near the Clairton Coke Works, according to Allegheny County Health Department data. (Courtesy image)

These last exceedances could be a sign that air quality in 2021 will not be as clean. The steel industry, which was already in a slump and suffered even more during the early part of the pandemic, has rebounded. If the coke works returns to full capacity and decreases its coking times to meet increasing demand for steel, the air won’t be as clean again this year.

A representative for U.S. Steel responded to a request for comment by sending a link to a press release, which included statements from Trinity Consultants that suggest the decreases in pollution could’ve been due to other factors, such as decreased car travel.

What does the ‘F’ grade mean?

The American Lung Association assigns a grade for the whole Pittsburgh metropolitan area but the grade is based on its most unhealthy air. So the region’s “F” grade specifically reflects the air quality for people living near the Clairton Coke Works.

The county’s air quality continues to improve at a faster rate than other areas, Kelly said. In 2019, Pittsburgh was one of only two cities, along with Seattle, to show fewer unhealthy air days than the previous year, according to last year’s ALA report. The ALA doesn’t directly compare how fast areas are improving, Stewart said, but did note that the Pittsburgh region has improved its ranking compared to past years.

The Pittsburgh metro area fell from being the 30th worst city for ozone pollution to the 35th, compared to last year’s ALA report. It moved from from 8th to 9th worst for year-round particulate pollution and remained the 16th worst for short-term particulate pollution.

A silver lining

An April 7 spike in polluted air in the Mon Valley could show a silver lining for even further improvement. The air quality near the Clairton Coke Works looked like it would exceed federal health standards, Kelly said. It was confusing, he said, because the air quality isn’t typically that bad during such a mild temperature inversion.

U.S. Steel happened to be taking a couple of its coke ovens offline that day for maintenance. And it voluntarily extended the amount of time they were offline by two hours after the health department requested it, Kelly said. The company took an additional stack offline until midnight.

By the end of the 24-hour period, the air quality had dipped just below the EPA standard for unhealthy air that day.

This is the kind of action that the health department hopes U.S. Steel will begin to take more regularly when the weather suggests the air quality is bad. The health department is introducing a proposed rule this month that would require U.S. Steel to come up with a plan. The rule could come up for a vote as soon as September, Kelly said. 

In the statement from U.S. Steel, a representative wrote: “U. S. Steel has demonstrated by actions the willingness to do its fair share during inversions to reduce impacts of [particulate pollution] in the Mon Valley area, and encourages the Allegheny County Health Department to ensure that all local and regional emissions sources are factored into the solution.”

Representatives for U.S. Steel already voted in favor of the rule at a subcommittee meeting on air quality, Kelly said. And this latest voluntary action shows some hope that it will comply, he said.

“That is hopeful that they are able to respond,” he said. “It’s something we haven’t seen before. That’s demonstrating maybe a new possibility.”

Oliver Morrison is PublicSource’s environment and health reporter. He can be reached at or on Twitter @ORMorrison.

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Oliver Morrison is a general assignment reporter at WESA. He previously covered education, environment and health for PublicSource in Pittsburgh and, before that, breaking news and weekend features for...