Coal, the dirtiest of fossil fuels, is far more harmful to human health than previously thought, according to a new report, which finds that coal emissions are associated with a mortality risk twice that of fine particles suspended in the air from other sources.
The research, published Thursday in the journal Science, linked coal pollution to 460,000 deaths among Medicare beneficiaries aged 65 and older between 1999 and 2020.
Yet the study also found that during this period, the closure of coal-fired power plants in the United States, coupled with the installation of scrubbers in smokestacks to “clean” coal exhaust, had salutary effects. Deaths attributable to coal plant emissions among Medicare beneficiaries fell 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, lead author of the study and assistant professor of environmental engineering at George Mason University, said in an interview. “We’ve made progress and it’s really good.”
Researchers from six universities collected data on emissions from 480 coal-fired power plants between 1999 and 2020. They used atmospheric modeling to track how sulfur dioxide turned into particles and where it was transported by the wind, then examined millions of Medicare patient deaths by zip code.
Although the researchers could not identify the exact causes of death, the statistical model showed that areas with more airborne anthrax particles had higher death rates.
According to the researchers, some 138 coal plants each contributed to at least 1,000 additional deaths, and 10 plants were linked to more than 5,000 deaths each.
While fine particles, known as PM 2.5, are frequently examined for their health risks, researchers have found that inhaling these fine particles from coal exhaust is particularly deadly.
Inhaling coal exhaust was associated with more than double the risk of mortality compared with inhaling fine particles from other sources, the researchers determined.
They also published a online tool showing deaths attributed to individual coal-fired power plants.
“We can’t say how long these people would have lived without exposure,” Dr. Henneman said. “But we say they died earlier than they would have because of this coal pollution.”
Requiring coal-fired power plants to “clean up” the pollutants they emit, removing sulfur dioxide using a cloud of water droplets, has been a game-changer for public health.
After scrubbers were installed in 2009 and 2010 at the Keystone Power Plant in Pennsylvania, the average number of annual deaths linked to the plant fell from 640 to 80, the researchers found. They also found that the average level of coal PM 2.5 in the United States fell to 0.07 micrograms in 2020, compared to 2.34 micrograms per cubic meter of air in 1999.
“Today, people are living longer without as much coal pollution in the air,” Dr. Henneman said. “This is the greatest achievement.” Coal consumption is declining in the United States, but it is increasing worldwide. It is expected to peak in 2025, when renewable energy sources are expected to become the main source of electricity generation.
The new study published in Science adds to growing evidence of the health benefits that come from moving away from burning fossil fuels, particularly for vulnerable populations.
In California, according to one study, the addition of 20 zero-emission vehicles per 1,000 residents in a given ZIP code correlates with a 3.2% drop in the rate of asthma-related emergency room visits. published earlier this year in the journal Science of the Total Environment.
In Chicago, the closure of three coal-fired power plants was followed by a 12 percent decrease in asthma-related emergency room visits for children aged 4 and under living in the area compared to rates in more distant locations, according to a 2021 study published in the American Journal of Public Health.
And after the closure of a large coal processing plant in Pittsburgh in 2016, there was an immediate 42 percent drop in weekly hospital visits for heart problems among nearby residents, another study found. The health benefits continued, with 33 fewer hospitalizations for heart disease on average in each of the three years after the plant closed compared to the previous three years.
In May, the Environmental Protection Agency proposed new rules that would limit the amount of pollutants power plants could release, and estimated the climate and health benefits could reach $85 billion. But given the deadly nature of coal particles, Dr. Hennemen said the benefits would likely be much greater. Tighter restrictions on tiny airborne particles could also lead to a 7% drop in death rates among black and low-income seniors who have long been subjected to the nation’s most polluted air, according to a study published earlier this year.