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Dr. Deborah Gentile knows how air pollution leads to debilitating conditions such as asthma.
In the working-class Mon Valley suburb of Clairton, home to her asthma clinic — and, not so incidentally, the largest coke works operation in the U.S. — one out of every four schoolchildren is growing up with asthma. That’s three times the national average. And 60 percent of those with the condition are deemed “uncontrolled.”
In 2018, when a Christmas Eve fire at Clairton Coke Works damaged and put offline pollution-control equipment, a paper in the journal Toxics showed that the rate of outpatient and emergency room visits for asthma exacerbations doubled.
“The first thing you want to do when you get asthma is you want to limit exposure to triggers — but you can’t avoid air pollution,” Gentile says. “When someone asks about it, I basically have to point out what we know: the Environmental Protection Agency (EPA) has pulled together lots of data. And we have a very high degree of certainty that air pollution is linked to asthma … The EPA recognizes that elevated levels of sulfur dioxide and PM2.5 trigger asthma. It’s not up for debate. It’s proven.”

The debate over further restricting PM2.5 — shorthand for particulate matter air pollutants many times smaller than the width of a human hair that can penetrate the lung barrier and enter the blood system — was reignited in January, when three important studies were released as the Biden Administration and EPA were considering whether or not to tighten regulations.
Currently, the EPA sets the PM2.5 bar at 12 micrograms per cubic meter, though the World Health Organization (WHO) recommends tighter restrictions. Proposals for the new EPA standards are expected this spring.
The three studies and related research, which drew praise from Pittsburgh-area environmental advocates, showed Black and Latino Americans are more likely than their white neighbors to breathe polluted air, that older Americans face serious health risks from even low levels of air pollution, and that elderly Americans living near fracking operations face a heightened rate of mortality.
Then, there’s U.S. Steel’s Clairton Coke Works, which repeatedly has been fined for exceeding pollutant limits. Gentile says Clairton residents who cannot breathe easily see the coke works — which, paired with Edgar Thomson Steel Works in Braddock, produces 70 percent of all PM2.5 pollution in the region — as the root of their problems.
“They feel helpless,” Gentile says. “They feel like no one is listening to them and no one will do anything at all about it.”
‘A reckoning’
Air pollution has improved in many American cities since 2000 — even in Pittsburgh, a city that infamously, generations ago, had to switch on streetlights at noon because the air, thick with soot and smog, darkened the midday sky.
Last year on Jan. 26, the Allegheny County Health Department reported that all eight county air quality monitors met federal standards for the first time. The monitors measure carbon monoxide, nitrogen oxide, ozone and PM2.5.
“There’s been great improvement and we give credit where credit is due,” says Kevin Stewart, director of environmental health, advocacy and public policy for the American Lung Association. “But, also, we have to remind everyone there are still serious problems with air pollution. From that perspective, there’s more that needs to be done.”
A Harvard T.H. Chan School of Public Health study out this month illustrates that ZIP code by ZIP code, racial minorities still are more likely than white Americans to breathe polluted air.
And experts say the trend is happening right here in Pittsburgh.
Published on Jan. 12 in the journal Nature, the study analyzes PM2.5 readings in 32,000 postal ZIP codes between 2000 and 2016, and concludes that areas with higher than average white and Native American populations consistently were exposed to less pollution than areas with higher than average Black, Asian and Hispanic or Latino populations.
“Our study, which highlights the relative disparities in PM2.5 exposure in the U.S., is particularly timely given current crises the country is facing, such as a reckoning with racism as well as disparities in Covid-19 outcomes,” says Francesca Dominici, a senior author of the study.
According to the Harvard study, previous research showed racial and ethnic minorities and lower-income groups in the U.S. are at higher risk of premature death from exposure to PM2.5 air pollution than other groups. The new research by Dominici and their team, however, linked demographic data from the U.S. Census Bureau and American Community Survey during the course of 17 years with nationwide PM2.5 data estimated from machine learning models that were based on satellite observations and atmospheric chemistry models.

Pittsburgh Mayor Ed Gainey says these trends are no secret to the communities that live locally with polluted air.
“Communities of color and working-class families have faced environmental injustices and detrimental health effects due to poor air quality in excess of the general population,” says Gainey, who grew up in the city suffering from asthma, which forced many visits to Children’s Hospital of Pittsburgh. “The Pittsburgh metropolitan area ranks as one of the top 10 most polluted areas in the country. Our Black and Brown populations have been subject to these health risks at an alarming rate … We must invest in environmental justice solutions to combat this crisis and truly build a city for all.”
Until recently, many Pittsburghers were breathing air that didn’t meet all federal EPA standards. After the closure of Shenango Coke Works on Neville Island in 2016 and other measures, air quality improved countywide.
According to the Harvard study, the amount of air nationwide above the federal standard dropped from 57.3% in 2000 to 4.5% in 2016.
Air pollution, however, continues to be a looming problem facing societies worldwide. In 2019, 99% of the planet’s population was living in places where WHO air quality guidelines were not met.