Limited Exposure to Air Pollution Linked to Premature Death

Exposure to levels of air pollution that fall below current safety standards may be dangerous for elderly patients.

A new study published by the Journal of the American Medical Association found that even short-term exposure to fine particulate air pollution and ozone can increase the risk of premature death among older Americans.

The risk of premature death linked to air pollution exposure was observed to be higher among seniors who were low-income, female, or black, according to the study.

“This the most comprehensive study of short-term exposure to pollution and mortality to date,” said senior author Francesca Dominici, PhD. “We found that the mortality rate increases almost linearly as air pollution increases. Any level of air pollution, no matter how low, is harmful to human health.”

Previous studies have shown that fine inhalable particulates (PM_2.5) and ozone are associated with higher mortality rates. Currently, the EPA considers long-term exposure to PM_2.5 to be safe if it averages 12 micrograms per cubic meter of air (μg/m³) or less per day annually. The 8-hour standard for warm-season ozone is 70 parts per billion (ppb), according to the study.

In the study, the authors evaluated air pollution exposure using prediction models of estimated daily PM_2.5 and ozone for the country. Then, the researchers linked these data with mortality data from Medicare patients between 2000 and 2012. During the 13-year period, 22 million study patients died.

The authors discovered that each 10 μg/m³ increase in PM_2.5 was linked to a 1.05% increase in the daily mortality rate, according to the study. Additionally, a 10-ppb daily increase in warm-season ozone was associated with 0.51% increase in the mortality rate.

The authors noted that if applied to all American seniors, this finding can have a significant impact on public health.

If daily PM_2.5 increased 1 µg/m³ over 1 summer, an additional 550 deaths annually would occur, with 7150 more deaths occurring over the 13-year period, according to the study.

The authors also projected that a daily ozone increase of 1 ppb over 1 summer would result in 250 extra deaths per year and 3250 deaths over the course of the study.

Notably, specific subgroups were susceptible to the effects of short-term air pollution.

Among patients with dual eligibility for Medicaid and Medicare, mortality linked to elevated PM_2.5 was 3 times higher compared with Medicare enrollees, according to the study.

Women and non-whites also had a 25% increased risk of premature death compared with patients who were men or white.

The authors hypothesized that poverty, unhealthy lifestyle, or diminished access to health care may be involved with these findings.

“No matter where you live—in cities, in the suburbs, or in rural areas—as long as you breathe air pollution, you are at risk,” said lead author Qian Di.