January 22, 2009

Cleaner Air Means Longer Life Spans

A federal study found Americans are living an average of five months longer thanks to cleaner air over the past two decades, according to a recent Associated Press report.

Researchers believe the findings are the first to show that cutting air pollution translates into longer lives.

Americans' average life span increased almost three years to 77, between the time frame of 1978 and 2001. Researchers from Brigham Young University and Harvard School of Public Health reported in Thursday's New England Journal of Medicine that as much as 4.8 months of that can be attributed to cleaner air.

Experts agree the difference is noteworthy.

"It shows that our efforts as a country to control air pollution have been well worth the expense," said Dr. Joel Kaufman, a University of Washington expert on environmental health.

For many years, scientists have believed the grit in polluted air, or particulates, can lodge deep in the lungs and raise the risk of lung disease, heart attacks and strokes. The grit originates from factories, power plants, and diesel-powered vehicles.

Congress passed a revised Clean Air Act in 1970 that gave the Environmental Protection Agency the power to set and enforce national standards to protect people from particulate matter, carbon monoxide, and other pollutants.

The law is widely credited with improving the nation's air quality through technologies like catalytic converters on cars and scrubbers at new factories.

Researchers used government data to track particulate pollution levels over two decades in 51 U.S. cities; they compared these changes to life expectancies calculated from death records and census data. They also adjusted the results to account for variables might affect life expectancy like smoking habits, income, education and migration.

They found on average, particulate matter levels fell from 21 micrograms per cubic meter of air to 14 micrograms per cubic meter in the cities studied. At the same time, Americans lived an average 2.72 years longer.

"We saw that communities that had larger reductions in air pollution on average had larger increases in life expectancies," said the study's lead author, C. Arden Pope III, a Brigham Young epidemiologist.

"This finding provides direct confirmation of the population health benefits of mitigating air pollution," Daniel Krewski, who does pollution research at the University of Ottawa in Canada, wrote in an accompanying editorial.

The study was partly funded by the Centers for Disease Control and Prevention and EPA.


On the Net: