Clean air may mean a longer life

Cleaning up air pollution translates into measurable increases in life expectancy, according to a study conducted by BYU and Harvard School of Public Health. In an examination of 51 American cities, researchers showed that life expectancy increased an average of nearly three years. And the thank-you for about five months of that is owed to better air quality.

Their findings are being published in the Jan. 22 New England Journal of Medicine.

Earlier studies clearly showed dirty air makes people sick, said C. Arden Pope III, Brigham Young University epidemiologist and lead author. "Over the last few decades, the United States as a matter of public policy has made substantial efforts to improve air quality. This has provided us with an opportunity similar to a nationwide natural experiment. "

The question was whether cleaner air really improves health. And the answer, he said, is definitely yes. "Our results suggest long-term reductions in air pollution can contribute to a significant and measurable increase in life expectancy."

The better the cleanup, the better the gains in terms of longevity, they found. After controlling for factors such as smoking, population changes, income, education, migration and demographics, the researchers found those who make the greatest improvement to air quality see the greatest gains in longevity.

They matched two sets of data from 51 American cities: Changes in air pollution between 1980 and 2000 and differences in life expectancies over those years. In the cities that had been the most polluted and cleaned up the most, the cleaner air added about 10 months to a resident's life. On average in the study cities, people were living nearly 2.7 years longer at the end of the two-decade study period. As many as five of those months came because of better air quality. Other studies show these gains likely come from reductions in heart and lung disease that go along with air pollution.

For every decrease of 10 micrograms per cubic meter of particulate pollution in a city, the residents' average life expectancy increased more than seven months. In the 1980s and '90s, most of the study cities averaged a drop of PM2.5 levels from 21 micrograms to 14 micrograms; Pittsburgh and Buffalo were among cities that dropped about 14 micrograms.

Salt Lake City and Utah Valley were among the study areas, Pope said, and the Wasatch Front falls "somewhere in the middle" for air quality, despite the current unhealthy inversion.

"There is an important positive message here that the efforts to reduce particulate air pollution concentrations in the United States over the past 20 years have led to substantial and measurable improvements in life expectancy," said co-author Douglas Dockery, chair of Environmental Health at Harvard School of Public Health.

"It's really a good news situation," Pope said. "Cleanup efforts we're making are having payoffs and there are opportunities to have continued returns to our efforts. We're making progress."

The study was funded by the federal government and private sources.

E-mail: lois@desnews.com