Better Air Quality Can Add About Five Months to Life Expectancy, Harvard Study Suggests

By Elizabeth Lopatto

Cleaner air added about five months to life expectancy in the U.S. over two decades, according to a study by Harvard School of Public Health and Brigham Young University researchers.

Decreasing pollution from fine air particles by about one- third, or 7 micrograms per cubic meter, was responsible for an almost five-month increase in longevity, data from 51 cities showed. In the cities that cleaned up the most, including Pittsburgh and Buffalo, residents added as much as 10 extra months to their lives, according to the report in tomorrow’s New England Journal of Medicine.

Pollution from small particles is known to cause heart attacks, early death, decreased lung function and asthma, according to the U.S. Environmental Protection Agency. The particles, which come from coal plants, car exhaust, fireplaces, furnaces and other sources, are common in urban areas and were more tightly regulated beginning in 1997.

“Past reductions in air pollution have improved life expectancy,” said the study’s lead author, C. Arden Pope, a professor of economics at Brigham Young University in Provo, Utah. “This tells us policy is paying off in terms of human longevity as well as environmental quality.”

The study’s 51 cities included Boston, New York, Philadelphia, Washington, Pittsburgh, Atlanta, Houston, Dallas, Oklahoma City, Denver, San Diego, Los Angeles, San Francisco, Portland, Seattle, Minneapolis, St. Louis, Chicago and Indianapolis.

Analyzing Longevity

The researchers matched life-expectancy data from the counties surrounding the cities with data on air quality, comparing two periods: 1979 through 1983, and 1999 through 2000. The scientists then analyzed the data by removing other variables that could affect life span such as income, education and cigarette smoking.

Americans were living about 2.7 years longer at the end of the study compared with the start. About 15 percent of that came from a reduction in air pollution from fine air particles that are about 2.5 micrometers, or one-25th the width of a human hair, the report found.

Pittsburgh and Buffalo had a decrease in fine-particle pollution of 14 micrograms per cubic meter. The average decrease was 7 micrograms per cubic meter, from 21 to 14 micrograms.

In some study sites, such as Pittsburgh, closing steel plants contributed drastically to improving the air quality, Pope said. Emissions standards for coal plants were major contributors in the Eastern states.

Sources of Particles

Much of the pollution from particulate matter comes from sources such as vehicle exhaust, furnaces, coal power plants, fires, steel mills, and copper smelters, Pope said.

Curbing emissions further would benefit the public health more. The study found that in areas where fine-particle levels decreased 10 micrograms per cubic meter, residents gained an extra seven months of life.

Homeowners might consider adding a high efficiency particulate air, or HEPA, filter to their furnaces, and avoiding burning things such as incense. Cars that burn less fuel will contribute less to pollution as well, Pope said.

“As a matter of public policy, we need to decide how much we want coal-fired power plants to emit,” Pope said.

The study was funded by the Centers for Disease Control and Prevention, the Environmental Protection Agency, the National Institute of Environmental Health Sciences and Brigham Young University.