Decreased air pollution leads to higher survival

Decreased air pollution leads to higher survival

A Harvard University study has proved that a reduction in the amount of fine particulate pollutants in air leads to greater survival rates.

Previous studies have established a direct link between the presence of fine particulate matter equal to or less than 2.5 microns in diameter i.e. PM2.5 and mortality rates in a population. The latest research has for the first time demonstrated that a decrease in PM2.5 can actually translate into reduced mortality.

According to Dr. Francine Laden, professor at Harvard Medical School in Boston and the lead researcher of the study, “This reduction was observed specifically for deaths due to cardiovascular and respiratory disease and not from lung cancer, a disease with a longer latency period and less reversibility.”

The research team based their study on the previous Harvard Six Cities study linking PM2.5 to mortality. Laden's team examined the follow-up data of the study which spanned the next eight years (1990 to 1998) when the levels of air pollution went down in most of the cities under consideration.

The population studied during the follow up included 8,100 residents of Steubenville, Ohio; Kingston and Harriman, Tennessee; Topeka, Kansas; Watertown, Massachusetts; St. Louis, Missouri; Portage, Wyocena and Pardeeville, Wisconsin. It was observed that with a fall in PM2.5 levels, the mortality rates in these cities also dropped. The mortality relative risk in the follow-up period was 73% as compared to the original study period.

The findings published in the 'American Journal of Respiratory and Critical Care Medicine' are like a silver lining to a dark cloud as they suggest that the harmful effects of air pollution are “at least in part reversible.”

“The practical implication is that pollution reduction, even beyond the relatively low levels that have been achieved in the past half-century, will lead to public health benefits,” remarked Dr. Bert Brunekreef of the University Medical Center in Utrecht, The Netherlands.