Short-term air pollution exposures up death risk in elderly

Previous studies have shown that fine inhalable particles (PM2.5) and ozone -- particularly 'warm-season ozone', which occurs from April to September -- are linked with increased mortality rates. 

The new findings showed that for each 10 µg/m3 (microgram per cubic metre air) daily increase in PM2.5 and 10 ppb (parts per billion) daily increase in warm-season ozone, the daily mortality rate increased by 1.05 per cent and 0.51 per cent, respectively. 

While this may seem a small increase, the health impact is enormous if it's applied to the whole population of seniors. 

"We found that the mortality rate increases almost linearly as air pollution increases. Any level of air pollution, no matter how low, is harmful to human health," said Francesca Dominici, Professor from Harvard T.H. Chan School of Public Health.

Further, among the low income group, the mortality increase linked with increased PM2.5 was found to be three times higher. 

Women and non-whites also faced a mortality risk that was 25 per cent higher than those who were male or white. 

Poverty, unhealthy lifestyle, or poor access to healthcare may play a role in such disparities, the researchers stated.

"No matter where you live -- in cities, in the suburbs, or in rural areas -- as long as you breathe air pollution, you are at risk," added Qian Di, from the varsity.

For the study, published in the Journal of the American Medical Association (JAMA), the researchers assessed daily air pollution exposures of people living in 39,182 zip codes in the US over a 13-year period from 2000-2012.

The results showed that day-to-day changes in fine particulate matter and ozone exposures were significantly associated with higher risk of all-cause mortality at levels below current air quality standards, suggesting that those standards may need to be re-evaluated.