MONDAY, November 27, 2023 — There are different kinds of ultra-fine particles that can hurt your health when you take them in from dirty air.

A new study shows that fine particle pollutants (PM2.5)—particles that are 2.5 microns or less in diameter—seem to double the risk of dying too soon over time if they come from coal-fired power plants instead of other sources.

PM2.5 from coal has been dealt with like it’s another pollutant in the air. But it’s much worse than we thought, and the number of deaths it causes has been seriously underestimated, lead author Lucas Henneman said in a news release from Harvard University. He works at George Mason University in Fairfax, Virginia, as an assistant professor of civil, environmental, and building engineering.

People from George Mason, Harvard, and the University of Texas at Austin led the project. The team wrote about what they found in Science on November 23.

They used Medicare statistics from more than 20 years, from 1999 to 2020, for their study.

The researchers think that over 460,000 deaths in the U.S. during the study time may have been caused by coal PM2.5. Henneman and his colleagues said that most of these deaths happened between 1999 and 2007, which was when coal PM2.5 levels were highest.

Scientists have known for a long time that PM2.5 can get stuck deep in the lungs of humans, which is not good.

But until now, no one knew if it made a difference where the PM2.5 came from.

As countries argue about their energy sources and as coal remains a strong, almost mythical figure in American energy history, our findings are very useful to policymakers and regulators as they weigh the need for cheap energy with the high costs to health and the environment, said Francesca Dominici, a professor of biostatistics, population, and data science at Harvard and a co-author of the study.

The study, which was paid for by the National Institutes of Health, also looked at pollution from 480 coal plants in the United States during the same time period.

In the short run, the team looked at how these emissions moved across land areas to make exposure fields.

They looked at data from exposure fields and Medicare records on seniors who lived and died in those places from 1999 to 2016.

A rise in coal PM2.5 levels in the air was linked to a 1.12% rise in death rates in the area. This was twice as much as an increase in death rates caused by any other source of PM2.5 in the area.

By going deeper into the data, the team was able to figure out how much each power plant contributed to the death rate in that area.

Ten out of the 480 plants studied are thought to have caused an extra 5,000 deaths over the course of the 20-year study.

There was good news, though Since 2007, when the number of coal-fired power plants in the U.S. started going down, so did the number of these kinds of deaths.

The most deaths from coal happened in 1999, but by 2020, that number had dropped by about 95% because coal plants had shut down or put in scrubbers, Henneman said.

I see this as a success story, Corwin Zigler, lead author of the study and associate professor of statistics and data sciences at UT Austin, said in a news release. Coal power plants were a big problem that U.S. policies have already substantially fixed.

Still, he said, we haven’t completely removed the burden. This study helps us understand how health will continue to improve and lives will be saved if we move even further towards a future powered by clean energy.

Sources

• Harvard T. Chan School of Public Health, news release, Nov. 23, 2023

Disclaimer: Note that the statistical information in medical articles only shows broad trends and does not apply to specific people. Different things can make a big difference. When making decisions about your own health care, you should always get personalised medical advice.