Any decrease in air pollution leads to longer lives, study finds

Saturday, December 08, 2012 by: David Gutierrez, staff writer
Tags: air pollution, longevity, study

(NaturalNews) Even a small decrease in air pollution can lead to significant increases in life expectancy, according to a study conducted by researchers from Harvard University and published in the journal Epidemiology.

"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," lead author Andrew Correia said.

Numerous studies have shown that improved air quality leads to lower rates of various health problems and increases life expectancy. But because many of these studies were conducted between 1980 and 2000, when U.S. air pollution levels were steadily declining, some researchers have questioned whether the much smaller decreases that have occurred in this century would still have a health benefit.

The new study focused on levels of fine particulate matter, known as PM2.5 (indicating that the particles have diameters of 2.5 micrometers or less). It is well established that both acute and chronic exposure to PM2.5 is associated with a higher risk of cardiovascular and lung disease and death.

The researchers examined PM2.5 levels and life expectancy statistics in 545 counties across the United States between the years 2000 and 2007. In doing so, they expanded on a 2009 New England Journal of Medicine study that had found an association between increased life expectancy and reduced air pollution in 211 urban counties. In addition to examining more counties, the new study made use of more recent data and was able to examine both urban and rural areas.

Pollution control prolongs life

Even after controlling for other risk factors such as smoking prevalence, socioeconomic status and other demographic characteristics, the researchers found that every reduction of 10 micrograms per cubic meter of PM2.5 concentration increased the average life expectancy in a county by 0.35 years. Decreases in air pollution appeared to improve the health of women more than men.

The connection between improved air quality and life expectancy was stronger in more urban and densely populated regions. Although the reasons for this were not clear, the researchers suggested that perhaps particulate matter in urban areas has a different composition than that in rural areas.

The study strongly demonstrates that continuing to decrease levels of air pollution has a measurable and significant benefit for human health and life span, the researchers said.

"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," senior author Francesca Dominici said. "However, the extent to which more recent regulatory actions have benefited public health [had remained] in question."

"This study provides strong and compelling evidence that continuing to reduce ambient levels of PM2.5 prolongs life."

The study was funded by the Environmental Protection Agency, the Harvard-NIEHS Center for Environmental Health, NIEHS, MRC Strategic Grant and the Health Effects Institute.

Sources:

http://www.hsph.harvard.edu