Americans Owe Five Months Of Their Lives To Cleaner Air
A new study
by researchers at Brigham Young University and Harvard School of Public
Health shows that average life expectancy in 51 U.S. cities increased
nearly three years over recent decades, and approximately five months
of that increase came thanks to cleaner air.
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 in the Jan. 22 issue of 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."
matched two sets of data from 51 cities across the nation: changes in
air pollution between about 1980 and about 2000; and residents' life
expectancies during those years. The scientists applied advanced
statistical models to account for other factors that could affect
average life spans, such as changes in population, income, education,
migration, demographics and cigarette smoking.
that had previously been the most polluted and cleaned up the most, the
cleaner air added approximately 10 months to the average resident's
life. On average, Americans were living 2.72 years longer at the end of
the two-decade study period; up to five months, or 15 percent, of that
increase came because of reduced air pollution. Other studies show that
these gains are likely coming from reductions in the cardiovascular and
cardiopulmonary disease that typically accompany air pollution.
"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 study co-author Douglas Dockery, chair of the
Department of Environmental Health at Harvard School of Public Health.
evaluated the impact of resulting decreases in particulate pollution on
average life spans in cities for which air pollution data were
available. In fact, researchers had to build life expectancy data for
the 214 counties that are part of the study's 51 metropolitan areas.
expectancy is the single most comprehensive summary of how people's
longevity is affected by factors like air pollution that cause early
death," said co-author Majid Ezzati, associate professor of
international health at Harvard School of Public Health. "We were able
to use routine mortality statistics to track longevity in all cities
over a long period of time and analyze how it has been influenced by
changes in air pollution."
found that for every decrease of 10 micrograms per cubic meter of
particulate pollution in a city, its residents' average life expectancy
increased by more than seven months. During the 1980s and 1990s the
average PM2.5 levels in the 51 U.S. cities studied dropped from 21 to
14 micrograms per cubic meter. In cities such as Pittsburgh and
Buffalo, the decrease was closer to 14 micrograms per cubic meter.
also observed gains in life expectancy even in cities that initially
had relatively clean air but had further improvements in air quality,
suggesting the continuing benefits to ongoing efforts to reduce air
researchers emphasized that there are other important and often
overlapping factors that influence life expectancy, but this study
demonstrated that improvements in air quality can contribute to
significant and measurable improvements in life expectancy.
The study was
funded by the Centers for Disease Control and Prevention, the
Association of Schools of Public Health, the Environmental Protection
Agency, the National Institute of Environmental Health Sciences, and
the Mary Lou Fulton Professorship at BYU.
For more information on Brigham Young University, visit www.byu.edu.