Coal, the dirtiest of fossil fuels, is far more harmful to human health than previously thought, according to a new report, which found that coal emissions are associated with double the mortality risk compared with fine airborne particles from other sources. From a report:

The research, published Thursday in the journal Science, linked coal pollution to 460,000 deaths among Medicare recipients aged 65 and older between 1999 and 2020. Yet the study also found that during that period the shuttering of coal plants in the United State, coupled with the installation of scrubbers in the smokestacks to “clean” coal exhaust, has had salubrious effects. Deaths attributable to coal plant emissions among Medicare recipients dropped from about 50,000 a year in 1999 to 1,600 in 2020, a decrease of more than 95 percent, the researchers found.

“Things were bad, it was terrible,” Lucas Henneman, the study’s lead author, and an assistant professor in environmental engineering at George Mason University, said in an interview. “We made progress, and that’s really good.” Researchers from six universities collected emissions data from 480 coal power plants between 1999 and 2020. They used atmospheric modeling to track how sulfur dioxide converted into particulate matter and where it was carried by wind, and then examined millions of Medicare patient deaths by ZIP code.

Though the researchers could not identify exact causes of death, the statistical model showed that areas with more airborne coal particulates had higher death rates. Some 138 coal plants each contributed to at least 1,000 excess deaths, and 10 plants were linked to more than 5,000 deaths apiece, the researchers found. While fine particulate matter, known as P.M. 2.5, is frequently examined for its health risks, the researchers found that inhaling those fine particles from coal exhaust was especially deadly.