A new study of Americans who receive Medicare benefits found that their risk of death and health consequences are significantly increased by certain air pollutants, even at levels deemed safe by the Environmental Protection Agency.
Harvard School of Public Health researchers evaluated how the mortality of all 60 million Americans on Medicare ― the vast majority are 65 and older ― was affected by fine particulate matter and ozone pollutants from 2000 to 2012.
The study, published Wednesday in the New England Journal of Medicine, sheds light on the relationship between pollution and longevity and presents a case for the EPA to change its National Ambient Air Quality Standards (NAAQS), which outline acceptable concentrations of these pollutants, the Harvard researchers wrote.
“These findings suggest that lowering the annual NAAQS may produce important public health benefits overall, especially among self-identified racial minorities and people with low income,” whose mortalities, the researchers found, are particularly affected by air pollution.
Under NAAQS, concentrations of fine particulate matter (PM) ― particles of less than 2.5 micrometers in diameter ― must be less than 12 micrograms per cubic meter of air. Ozone concentrations must measure less than 50 parts per billion.
The study found that PM and ozone concentrations far lower than that can shorten life for people in this age group. Exposure to as little as 5 micrograms per cubic meter of PM or to as little as 30 parts per billion of ozone may shorten lifespans, the researchers wrote.
In the years the study was conducted, PM concentrations ranged from 6.21 to 15.64 micrograms per cubic meter, and ozone concentrations ranged from 36.27 to 55.86 parts per billion.
“In the entire Medicare population, there was significant evidence of adverse effects related to exposure to [fine particulate matter] and ozone at concentrations below current national standards,” the authors wrote.
The pollutants are linked to a variety of deadly medical conditions, including lung diseases and heart attacks.
The findings come as President Donald Trump takes steps to undo Obama-era emissions-cutting rules, drastically cut the EPA’s budget and withdraw from the Paris agreement on climate change.
The study also found that each 10-microgram increase of PM per cubic meter was associated with a 7.3 percent increase in mortality among Medicare recipients during the time of the study. For every increase of 10 parts per billion in ozone concentration, mortality among Medicare recipients rose 1.1 percent.
The lethality of those pollutants was most pronounced among ethnic minorities and low-income citizens, the study authors noted.
Among black Medicare recipients, for example, the study found the effect of PM on their mortality was three times as high as that of the overall study population.
CORRECTION: A previous version of this story said particulate matter was measured in micrograms. It is measured in micrometers.