The air we breathe has gotten much cleaner in the past 40 years because of hard-won federal standards. And if those standards were just a bit more stringent, thousands of premature deaths could be prevented every year, suggests a recent study of more than 60 million Americans.
The findings, based on publicly available health and mortality statistics for every person in the lower 48 states who was enrolled in Medicare between 2000 and 2012, represent the most “bulletproof” link to date between air pollution and death, says Francesca Dominici, one of the researchers.
Most previous studies that found such a link looked at smaller groups that were not nationally representative, or focused only on areas closely monitored by the Environmental Protection Agency, according to the study, published June 29 in The New England Journal of Medicine. This new work zeroes in on Americans ages 65 and older, the population that accounts for two-thirds of all U.S. deaths, the authors wrote.
“The data platform is unprecedented,” says Dominici, a professor of biostatistics at the Harvard T.H. Chan School of Public Health and co-director of the Harvard Data Science Initiative. The analysis by Dominici and her colleagues combined the Medicare data with ZIP-code-specific estimates of individuals’ annual exposure to ground-level ozone and to small particles that can lodge in our lungs. Researchers have known for years that high levels of this “fine particulate matter” or of ozone are associated with an increased risk of death. And hundreds of studies have linked particulate pollution with heart disease, asthma, and deaths in cities, according to an editorial in the same issue of the journal.
The new research more or less confirmed these risks. But the study is one of the first with enough statistical power to suggest that mortality is higher even when pollution is at lower levels than EPA allows. Strikingly, the numbers also suggest that black people are at three times the general population’s risk of dying from long-term exposure to particulate matter.
The team estimated the number of lives that could be saved if current regulations became just one unit more stringent — that is, one microgram of fine particulate matter per cubic meter, or one part per billion of ozone. (The current EPA standard for long-term exposure to small particles is 12 micrograms per cubic meter per year.) A one-unit drop for small particles would save about 12,000 lives a year and a one-unit drop for ozone would save about 1,900 lives, Dominici says.
The findings cast a harsh light on recent actions by the Trump administration, such as requiring the EPA to review the Obama-era rules curtailing emissions from coal-fired power plants — a major source of particulate pollution.
EPA officials and scientists are reviewing research related to national air-quality standards, according to this online report by the agency. A schedule on the last page of the report indicates that it could take five more years to finalize any policy changes based on the review. For Americans whose lives literally depend on clean air, that seems like a long time to wait.