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SAN FRANCISCO -- For neighborhoods near a major coking operation in Pittsburgh, its shutdown at the end of 2015 was followed by markedly lower rates of respiratory disease hospitalizations, researchers reported here.

Inpatient admissions for chronic obstructive pulmonary disease (COPD) among area residents were steadily increasing during 2013 to 2015. But from 2016 onward, they declined, such that in 2019, case numbers were about 40% lower than if the previous trend had continued, said Wuyue Yu and George Thurston, ScD, of NYU Langone Health in New York City.

A different pattern was seen for pediatric asthma admissions that nevertheless suggested a beneficial impact of the . Cases were already dropping prior to the shutdown, the researchers reported in a poster presented at the American Thoracic Society's annual meeting, reaching about 30 at the close of 2015. But following the coke works' closure, case counts dropped abruptly to about 15.

No changes in COPD or pediatric asthma hospitalization trends were seen at sites not exposed to the facility's emissions. There was also no apparent change in these outcomes near a similar coke plant on the opposite side of metropolitan Pittsburgh, , which still operates.

The Shenango operation was one of the , along with the Clairton facility. It was located on an island in the Ohio River about 5 miles northwest (i.e., upwind most days) of downtown Pittsburgh. Coke is an important heat source and reducing agent used in steelmaking; it's made by heating coal in the absence of oxygen. The process releases gases and other contaminants that cannot be completely scrubbed from plants' airborne effluents.

Not surprisingly, Yu and Thurston found that levels of certain air pollutants also declined in areas generally downwind from Shenango after the shutdown. Monitoring performed near the plant, and at a special site run by the Environmental Protection Agency about 7 miles to the southeast, showed "significant immediate reduction" in sulfur dioxide, particulate-matter sulfates, and toxic heavy metals including selenium, cadmium, and arsenic.

U.S. Steel has been under pressure to reduce emissions from the Clairton facility, after being for continual noncompliance with government standards. After initially promising a billion-dollar renovation of its remaining Pittsburgh-area operations, the company changed course last year, to simply reduce the coke works' scale (with a commensurate cut in jobs).

That plan was still greeted warmly by environmentalists in the region who believe that it will improve local air quality -- an expectation that got backing from Yu and Thurston.

"Interventions eliminating coal-coking air pollution significantly improve the air quality and respiratory health of the local community," they concluded from their own data.

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