WASHINGTON — Older Americans who regularly breathe even low levels of pollution from smokestacks, automobile exhaust, wildfires and other sources face a greater chance of dying early, according to a major study released Wednesday.
Researchers at the Health Effects Institute, a group that is funded by the Environmental Protection Agency as well as automakers and fossil fuel companies, examined health data from 68.5 million Medicare recipients across the United States. They found that if the federal rules for allowable levels of fine soot had been slightly lower, as many as 143,000 deaths could have been prevented over the course of a decade.
Exposure to fine particulate matter has long been linked to respiratory illness and impaired cognitive development in children. The tiny particles can enter the lungs and bloodstream to affect lung function, exacerbate asthma and trigger heart attacks and other serious illness. Earlier research has found that exposure to particulate matter contributed to about 20,000 deaths a year.
The new study is the first in the United States to document deadly effects of the particulate matter known as PM 2.5 (because its width is 2.5 microns or less) on people who live in rural areas and towns with little industry.
“We found a risk of dying early from exposure to air pollution, even at very low levels of air pollution across the United States,” said Daniel S. Greenbaum, president of the Health Effects Institute.
The findings come as the Biden administration is considering whether to strengthen the national standard for PM 2.5, which is currently set at a yearly average of 12 micrograms per cubic meter, a level higher than that recommended by the World Health Organization.
Researchers concluded that 143,257 deaths could have been prevented between 2006 and 2016 if the standard had been tightened to 10 micrograms per cubic meter.
“If we were to reduce PM 2.5, we would be saving a substantial amount of lives,” said Francesca Dominici, a professor of biostatistics at Harvard who led the study, which took four years to complete. “It’s highly significant.”
“This is important evidence for E.P.A. to consider,” Dr. Dominici added.
Other studies have linked fine soot pollution to higher rates of death from Covid-19, with Black and other communities of color particularly at risk because they are more likely to be located near highways, power plants and other industrial facilities.
The Biden administration has made tighter regulation of emissions from power plants, factories and other industrial sites central to its strategy to address environmental justice.
By law, the E.P.A. is required to review the latest science and update the soot standard every five years. The Trump administration opted not to strengthen the standard when it conducted the most recent review, despite growing scientific evidence of the harm to public health caused by particulate matter.
Using the public data of the 68.5 million Medicare recipients — nearly every American over the age of 65 — researchers focused on people living in rural areas and other places that are not well monitored by the Environmental Protection Agency, either because they are sparsely populated or because pollution levels are not considered as high as in cities or along the congested East Coast.
Karin Stein, 60, moved to Iowa from her native Colombia as a student in 1980 and now lives in Jasper County with her family. Even in her relatively rural area near Rock Creek State Park, she said, wildfire smoke exacerbates her heart condition and is a major concern.
“It’s idyllic,” she said. “But you have the Western wildfires, or it’s harvest time. We assume that there are no air quality issues. But that’s simply false.”
A spokesman for the E.P.A. said the agency was expected to propose a draft rule by summer and to issue a final rule by the spring of 2023.
Polluting industries are expected to lobby heavily against a stricter new soot pollution rule.
The American Petroleum Institute, which represents oil and gas companies, did not review the Health Effects Institute research but questioned the need for tighter pollution rules. In a statement the trade group said “the current scientific evidence indicates the existing standards are effectively designed to protect public health and meet statutory requirements.”
The institute noted that emissions of traditional pollutants like PM 2.5 have dropped significantly since the 1970s because of the use of cleaner automobile fuels and the rise of natural gas in power generation instead of coal.
Some experts said companies were resigned to the likelihood the Biden administration will tighten the rule, but were concerned about how far it might go.
“It’s a question of how much,” said Jeffrey Holmstead, a lawyer who served in the E.P.A. in both Bush administrations.
A significant reduction in allowable limits would be “very costly” for companies, Mr. Holmstead said. He also noted that in communities that do not have major industrial centers, much of the fine soot pollution comes from automobiles, making it difficult for state governments to regulate.
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“At what point do you say we’re going to prohibit any kind of combustion engines because everything contributes to PM 2.5?” Mr. Holmstead said. “And if you set a level that is overly-stringent, you basically prohibit any new economic development in certain parts of the country.”
Yet the science documenting the health consequences of exposure to air pollution has been mounting since Harvard University in 1990 produced its landmark “six cities” study, which found living in heavily polluted cities can shave two to three years off a person’s life.
Hazel Chandler, 76, lives in Phoenix and said she considered herself a prime example of someone living with the cumulative effects of more than 40 years of air pollution.
Ms. Chandler said that when she moved to Arizona from Southern California in 1977, the relatively clearer air was a relief. But as the city’s population exploded, so did her asthma and breathing problems.
“Sometimes we have several pollution days in a row, and I don’t need to look at the air quality alerts anymore,” she said. “I know.”
“I can tell by the pressure in my lungs and in my chest, the amount of coughing, I have a chronic cough from it,” Ms. Chandler. “I can tell if I wake up with a really bad cough, its probably a high pollution day.”
Ms. Chandler, a consultant with Moms Clean Air Force, a nonprofit environmental group, said she worried about older people with heart conditions and other health issues that can be exacerbated by pollution. But she’s even more concerned about young children.
“I moved to Phoenix when I was about 30 and it still has impacted my ability to breathe,” she said. “If it’s affecting older people, what is it going to do to the children who are living here and breathing this their whole life?”
Jennifer L. Peel, head of epidemiology at Colorado State University’s Department of Environmental and Radiological Health Sciences, said studying areas that are not well monitored presented a challenge because it could be difficult to validate levels of exposure to pollution.
But Dr. Peel, who was not part of the research team and independently reviewed the study, called it an “amazing first step” and said, overall, the study was the most comprehensive she had seen.