U.S. Air Pollution Limits Leave Residents at Risk for Early Death

09_16_15_Air Pollution Early Death Heart Disease
A new paper finds that exposure to particulate matter, spewed from automobiles, power plants and just about anything else that burns fuel, significantly raises the risk for early death, especially from heart disease. Mike Blake/Reuters

Air pollution is a killer. And right now, the U.S. government's standards for acceptable air pollution exposure permit enough of it to significantly increase one's risk of early death, especially from heart disease, according to the results of a large study released Tuesday.

The study, published in Environmental Health Perspectives, found that chronic exposure to 10 micrograms per cubic meter of particulate matter known as PM 2.5—one of the most ubiquitous forms of air pollution—increases the likelihood that a person will die an early death by roughly 3 percent, after controlling for all other causes. What's more, that level of exposure increases the risk that a person will die of heart disease by roughly 10 percent.

But the U.S. Environmental Protection Agency permits annual exposure of up to 12 micrograms per cubic meter of PM 2.5—pollution particles that spew from car tailpipes, power plants and just about every other source that burns fuel, as well from any crushing or grinding operation that produces dust. With a diameter smaller than 2.5 microns (a micron is one-millionth of a meter; 2.5 of them is about one-thirtieth of the width of a human hair), these particles are so small that they can penetrate deep into the lungs. The EPA has linked exposure to them to early death, cardiovascular diseases and a range of respiratory illnesses.

Based on the study's conclusions, exposure to 12 micrograms per cubic meter of PM 2.5 increases a person's risk of dying from heart disease by 12 percent in any given year, explains George Thurston, a professor of health and environmental medicine at New York University Langone Medical Center and lead author on the study. That means that the risk of dying early, in general, would be raised by about 3.6 percent at the permitted rate of exposure.

And that's just for communities that have brought their pollution in line with the federal standards. The EPA can designate an area as being in "nonattainment" of the standards, and require officials to develop a plan for how they'll curb emissions to meet them. But according to the American Lung Association's 2015 "State of the Air" report, around 44 percent of people in the United States live in counties that have "unhealthful levels" of either long-term or short-term ozone or particulate matter pollution. This means many, many people in the U.S. are exposed to levels of particulate matter far exceeding the EPA's limits—and are at a higher-than-normal risk for early death from heart disease or other pollution-related causes.

The discovery that exposure even below the U.S.'s own threshold for air pollution carries big health consequences and suggests that efforts to reduce air pollution for other objectives, like reducing power plant emissions to curb climate change, would have large, tangible benefits for human health locally. "That's a real policy implication," Thurston says, especially in a time when the adequacy of various EPA emissions rules is being actively debated; in June, the Supreme Court was asked to weigh in on whether the EPA had adequately considered the economic costs and benefits of its rule to curb toxic mercury emissions from power plants. In that case, the court ruled that the EPA must return to the drawing board and include an economic cost-benefit analysis in its plan for the rule.

"It is not rational, never mind 'appropriate,' to impose billions of dollars in economic costs in return for a few dollars in health or environmental benefits," Justice Antonin Scalia wrote in his opinion on that case.

But, Thurston says, the recent PM 2.5 study and others support the evidence that the economic benefits of reducing airborne pollution—and thereby reducing health care costs—are far greater than Scalia acknowledged.

The World Health Organization linked air pollution to 7 million premature deaths in 2012 alone, which amounts to 1 in every 8 people who died that year. Beyond cardiovascular disease, asthma, bronchitis and other related ailments, studies have emerged linking chronic air pollution exposure to the premature aging of the brain, cognitive delay in children, increased incidence of suicide, autism risk, early birth and low birth weight.