Asian Scientist (Jul. 9, 2013) – A new study, based on long-term data collected in China, has estimated the extent to which air pollution may shorten human lives. In particular, the study projected a significantly reduced life expectancy for people exposed to high levels of air pollution, produced by burning coal, in northern China.
The research, published in the Proceedings of the National Academy of Sciences, estimated that the 500 million Chinese who live north of the Huai River are set to lose 2.5 billion years of life expectancy, in total, due to the extensive use of coal to power boilers for heating throughout the region.
In comparison, the researchers found very different life-expectancy figures for an otherwise similar population south of the Huai River, where government policies were less supportive of coal-powered heating.
The paper also provided a generalized metric that can apply to any country’s environment: every additional 100 micrograms of particulate matter per cubic meter in the atmosphere lowers life expectancy at birth by three years.
In China, particulate-matter levels were more than 400 micrograms per cubic meter between 1981 and 2001, according to Chinese government agencies; state media have reported even higher levels recently, with cities including Beijing recording levels of more than 700 micrograms per cubic meter in January. (In comparison, total suspended particulates in the United States were about 45 micrograms per cubic meter in the 1990s.)
“Everyone understands it’s unpleasant to be in a polluted place,” said Professor Michael Greenstone, a senior author of the study.
“But to be able to say with some precision what the health costs are, and what the loss of life expectancy is, puts a finer point on the importance of finding policies that balance growth with environmental quality.”
A river runs through it
The research stems from a policy China implemented during its era of central planning, prior to 1980. The Chinese government provided free coal for fuel boilers for all people living north of the Huai River, which has long been used as a rough dividing line between north and south in China.
The free-coal policy means people in the north stay warm in winter—but at the cost of notably worse environmental conditions. Using data covering an unusually long timespan—from 1981 through 2000—the researchers found that air pollution, as measured by total suspended particulates, was about 55 percent higher north of the river than south of it, for a difference of around 184 micrograms of particulate matter per cubic meter.
Linking the Chinese pollution data to mortality statistics from 1991 to 2000, the researchers found a sharp difference in mortality rates on either side of the border formed by the Huai River. They also found the difference to be attributable to cardiorespiratory illness, and not to other causes of death.
“It’s not that the Chinese government set out to cause this,” said Greenstone.
“This was the unintended consequence of a policy that must have appeared quite sensible.”
Another reason to limit emissions
The researchers hope that the finding will have a policy impact not only in China, but also in other rapidly growing countries that are increasing their consumption of coal. Moreover, given the need to limit carbon emissions globally in order to slow climate change, they hope the data will encourage countries to think twice about fossil-fuel consumption.
“What this paper helps reveal is that there may be immediate, local reasons for China and other developing countries to rely less on fossil fuels,” said Greenstone.
“The planet’s not going to solve the greenhouse-gas problem without the active participation of China. This might give them a reason to act today.”
The article can be found at: Chen et al. (2013) Evidence On The Impact Of Sustained Exposure To Air Pollution On Life Expectancy From China’s Huai River Policy.
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Source: MIT; Photo: UniversityBlogSpot/Flickr.
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