The people of Calcutta and Mumbai may on average live three years longer with an improvement in air quality to meet World Health Organisation standards, new research suggests. For Delhi residents, the gain could be nine years.

A study released today by collaborating scientists in China, Israel and the US has found that every additional 10 micrograms per cubic metre of tiny particulate matter, sized 10 microns or less, reduces life expectancy by about six months.

The researchers, who used a unique social setting in two regions of China to study air pollution and life expectancy, have discovered a link they say could be applied to determine life expectancy gains in other countries with improved air quality.

They found that China’s decades-old policy to provide free coal to a region north of the Huai river had led to higher pollution in the north of the river than its south. Also, people north of the river lived about three years less than those in the south, the increase in the death rates linked to air pollution-driven heart disease, stroke, lung cancer or respiratory illness. The findings appeared today in the journal Proceedings of the National Academy of Sciences.

“Particulates’ impacts on the life expectancy in many parts of the world are similar to the effects of every man, woman and child smoking cigarettes for several decades,” said Michael Greenstone, director of the Energy Policy Institute at the University of Chicago, who led the study.

The scientists have used their results from China to develop an air quality-life index that allows them to determine the gain in life expectancy in different parts of the world if tiny particulate matter (PM) is reduced to safe or permissible levels as prescribed by national standards or the WHO. Continue reading…