Reducing Pollution Extends Life Expectancy

Jan. 22, 2009 -- Reducing pollution produces measurable health gains, according to a new study that found cleaner air had lengthened life expectancy by five months in 51 U.S. cities.

Researchers at Brigham Young University and Harvard School of Public Health found that average life expectancy increased by three years between 1980 and 2000 in those cities, and that approximately five months of that gain owed to cleaner air.

"Such a significant increase in life expectancy attributable to reducing air pollution is remarkable," said C. Arden Pope III, a BYU epidemiologist and lead author on the study, published in the New England Journal of Medicine.

"We find that we're getting a substantial return on our investments in improving our air quality. Not only are we getting cleaner air that improves our environment, but it is improving our public health."

The researchers compared data in 51 U.S. cities on changes in air pollution between those 20 years and the life expectancies of residents during those years.

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They applied advanced statistical models to account for other factors possibly affecting life spans, such as changes in demographics, income, migration, population, education and cigarette smoking.

Cities that had previously been the most polluted and saw the most extensive clean-ups added an average 10 months to residents' lives.

By the end of the study period, life expectancy had increased by 2.72 years in the cities studied, with up to five months, or 15 percent of that gain owing to reduced air pollution.

Other studies have shown that these gains probably owe to a decrease in cardiovascular and cardiopulmonary diseases often linked to air pollution.

Pope and study co-author Douglas Dockery of Harvard teamed up with other researchers on studies published in the early 1990s that found that "PM2.5" -- pollutants less than 2.5 microns in diameter -- had negative health effects.