A new study finds that cleaner air over the past two decades has added roughly five months to the average life expectancy in the United States.
Prior studies have shown that exposure to pollution coming from tailpipes and smokestacks is associated with an increased risk of respiratory disease and premature death.
The new, federally funded study is among the first to assess what happened to life expectancy when air quality — across the United States — began to improve.
Researchers at Brigham Young University and the Harvard School of Public Health studied associations between longevity and so-called fine-particulate air pollution in 51 cities.
Led by C. Arden Pope, a BYU epidemiologist, they studied the period from the late 1970s to the early 1980s — when clean air laws were just beginning to have an effect — and compared it with data from the late 1990s to early 2000s. They drew on census data and death records and, using statistical models, factored in other things that might alter life expectancy, such as smoking habits, income, education and migration.
In the 1980s and 1990s, these cities experienced an average 33 percent decrease in air pollution, the researchers found.
They concluded that improved air quality may add about five months to the average life span. Increases in life expectancy were even greater in communities that had larger reductions in air pollution. The results are published in the Jan. 22 issue of the New England Journal of Medicine.
With additional information from The Associated Press