Current limits on fine particulate matter in the air set by the U.S. Environmental Protection Agency (EPA) may not be sufficient to protect elderly people from the risk of premature death from air pollution, according to a large study from Harvard T.H. Chan School of Public Health.

Looking at 13 years’ worth of data from more than 13 million elderly people living in the Southeastern U.S., the new study, published in Epidemiology, found that for each 1 µg m-3 (roughly 10 percent) increase in the annual average concentration of PM2.5 (particles smaller than 2.5 microns in diameter) in the air in a particular region, mortality risk rose by 2 percent. The risk showed up even in areas where PM2.5 levels were below current EPA limits.

“We found that if particle concentrations could be reduced by about 10 percent, it would lower the death rates of people age 65 and older in the Southeastern U.S., saving 7,000 to 10,000 lives per year,” said Joel Schwartz, professor of environmental epidemiology and senior author of the study. “That would be a very large public health impact.”

While the link between long-term exposure to PM2.5 and increased mortality risk has been well documented over the past two decades, previous studies included mostly participants with high socioeconomic status, making it difficult to identify air pollution’s effects on those who are socially and economically disadvantaged. The new study looked at the entire Medicare-eligible population of seven Southeastern states. It also took a closer look at characteristics that potentially put people at greater risk from air pollution, such as diabetes.

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