CAMBRIDGE, MA -- A high level of air pollution, in the form of particulates produced by burning coal, significantly shortens the lives of people exposed to it, according to a unique new study of China co-authored by an MIT economist.
The research is based on long-term data compiled for the first time, and projects that the 500 million Chinese who live north of the Huai River are set to lose an aggregate 2.5 billion years of life expectancy due to the extensive use of coal to power boilers for heating throughout the region. Using a quasi-experimental method, 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.
"We can now say with more confidence that long-run exposure to pollution, especially particulates, has dramatic consequences for life expectancy," says Michael Greenstone, the 3M Professor of Environmental Economics at MIT, who conducted the research with colleagues in China and Israel.
The paper, published today in the Proceedings of the National Academy of Sciences, also contains 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. (By comparison, total suspended particulates in the United States were about 45 micrograms per cubic meter in the 1990s.)
Air pollution has become an increasingly charged political issue in China, spurring public protests; last month, China's government announced its intent to adopt a serie
|Contact: Vicki Ekstrom|
Massachusetts Institute of Technology