If air pollution were removed as a risk for death, people in the world could live at least a year longer and in India, which is battling a severe air pollution, the benefit would be even more -- about 1.5 years, says study.
"Here, we were able to systematically identify how air pollution also substantially shortens lives around the world," said lead researcher Joshua Apte from The University of Texas at Austin in the US.
"What we found is that air pollution has a very large effect on survival -- on average about a year globally," Apte added.
For the study, published in the journal Environmental Science and Technology Letters, the researchers looked at outdoor air pollution from particulate matter (PM) smaller than 2.5 microns.
These fine particles that can come from power plants, cars and trucks, fires, agriculture and industrial emissions can enter deep into the lungs, and breathing PM2.5 is associated with increased risk of heart attacks, strokes, respiratory diseases and cancer.
The team used data from the Global Burden of Disease Study to measure PM2.5 air pollution exposure and its consequences in 185 countries.
They then quantified the national impact on life expectancy for each individual country as well as on a global scale.
"A body count saying 90,000 Americans or 1.1 million Indians die per year from air pollution is large but faceless," Apte said.
"Saying that, on average, a population lives a year less than they would have otherwise -- that is something relatable," he added.
In the context of other significant phenomena negatively affecting human survival rates, Apte said this is a big number.
"For example, it's considerably larger than the benefit in survival we might see if we found cures for both lung and breast cancer combined," he said.
"In countries like India and China, the benefit for elderly people of improving air quality would be especially large. For much of Asia, if air pollution were removed as a risk for death, 60-year-olds would have a 15 per cent to 20 per cent higher chance of living to age 85 or older," Apte said.