From the Harvard Gazette, quoting from this paper in Science by Henneman, Choirat, Dedoussi et al, Mortality risk from United States coal electricity generation:

“Exposure to fine particulate air pollutants from coal-fired power plants (coal PM2.5) is associated with a risk of mortality more than double that of exposure to PM2.5 from other sources…Examining Medicare and emissions data in the U.S. from 1999 to 2020, the researchers also found that 460,000 deaths were attributable to coal PM2.5 during the study period — most of them occurring between 1999 and 2007, when coal PM2.5 levels were highest.”