Declining Air Pollution Levels Increase Life Expectancy

Harvard researchers say that lower pollution levels will continue to improve public health.

pollutionPollution photo via Shutterstock

Researchers at the Harvard School of Public Health (HSPH) found that lower air pollution levels in the United States has increased life expectancy and improved public health in 545 counties from 2000 to 2007. It is the largest study to date that looked for the beneficial effects on public health by reducing air pollution levels in the U.S. The study was published in the December 3rd online edition of the journal Epidemiology.

According to the study:

The study looked at the effects on health of fine particulate matter, small particles of 2.5 micrometers or less in diameter—referred to as PM2.5. Numerous studies have shown associations between acute and chronic exposure to fine particle air pollution and cardiopulmonary disease and mortality. Studies have also shown that reductions in air pollution are associated with reductions in adverse health effects and improved life expectancy. Air pollution has been declining steadily in the U.S. since 1980, but the rate has slowed in the years since 2000. The HSPH researchers wanted to know whether the relatively smaller decreases in PM2.5 levels since 2000 are still improving life expectancy.

Lead study author Andrew Correia says in the press release, “Despite the fact that the U.S. population as a whole is exposed to much lower levels of air pollution than 30 years ago—because of great strides made to reduce people’s exposure—it appears that further reductions in air pollution levels would continue to benefit public health.”

The research expanded on a 2009 study published in the New England Journal of Medicine. The new study looked at more recent data in both rural and urban areas and looked at two-and-a-half times more counties than the previous study. Urban areas showed the strongest association between declining air pollution and higher life expectancy. When asked why, researchers speculated that the composition of the particulates there may be different from that in rural areas.

Senior study author Francesca Dominici, professor of biostatistics at HSPH says in the press release, “Since the 1970s, enactment of increasingly stringent air quality controls has led to improvements in ambient air quality in the United States at costs that the U.S. Environ­mental Protection Agency has estimated as high as $25 billion per year. This study provides strong and compelling evidence that continuing to reduce ambient levels of PM2.5 prolongs life.”