Coal-Burning Shortens Lives in China, New Study Shows

A new study shows that air pollution from coal-burning home heating systems has shortened life expectancy in northern China by 5.5 years. Life expectancy in northern China was 5.5 years shorter than in southern China in the 1990s, and a health risk disparity lingers today, a difference almost entirely due to heart and lung disease related to air pollution from the burning of coal, a new study shows.

The findings come at a time when coal is on track to surpass oil as the world's top energy source and 2.8 billion people rely on wood, crop waste, dung, and other biomass to cook and heat their homes.

"We can now say with more confidence that long-run exposure to pollution, especially particulates, has dramatic consequences for life expectancy," said Michael Greenstone, economics professor at the Massachusetts Institute of Technology, who collaborated with researchers in China and Israel.

The air concentration of total suspended particulates (TSP) in the north was 55 percent higher than in the south, and life expectancies were 5.52 years lower, between 1981 and 2000, the researchers found. Since there are 500 million residents of Northern China, that means air pollution is associated with the loss of more than 2.5 billion life years of life expectancy, the study says. Northern China includes numerous cities that are perennially on the list of the world's most polluted metropolitan areas, including the capital city of Beijing; neighboring Tianjin; Lanzhou, in the Gansu province; and Harbin in Heilongjiang province.

Greenbaum added, however, that the study, for all its strengths, assumes that home heating systems are the source of the particulate pollution. Northern China also is home to most of the nation's coal-burning power plants, and could also be contributing to the health burden, he said. "I'd say the regional analysis and differences in air pollution are right on the money, but I'd be hesitant to say that any one coal-fired source is better than another," he said.

A Measure of Health Impact

The results suggest that long-term exposure to each additional 100 micrograms per cubic meter of TSP is associated with reduction in life expectancy at birth of about three years. Particulate-matter levels were more than 400 micrograms per cubic meter in China during the years studied. (Beijing made headlines in January when its air pollution levels reached a staggering 700 micrograms per cubic meter, but that was based on a number of pollutants, not just TSP particulates-those measured in this study.)

Although the researchers did not analyze mortality data from more recent years, they did compile air pollution data from 2003 to 2008 indicating that TSP concentrations remain 26 percent higher north of Huai River, "suggesting that residents of the north continue to have shortened lifespans," the study said. Greenstone said the researchers are continuing to work on an effort to gain access to more recent mortality data.

The life expectancies were calculated from 1991 to 2000, using mortality data derived from China's Disease Surveillance Points (DSP) system, a set of 145 sites chosen to be nationally representative so that it captures the nation's variation in wealth, urbanism, and geographic distribution. The study also included analysis on a wide range of other factors, including temperature data, education, manufacturing's share of employment, and the percent of residents with access to tap water, to rule out causes other than air pollution as the reason for the north-south disparity.

Greenbaum, of the Health Effects Institute, said the new study is likely to be given weight in policymaking in China because it was conducted in collaboration with Chinese researchers.

Marianne Lavelle, National Geographic


Phathutshedzo Osborne Magada, Forum for Environmental, Biological and Earth Scientists (FEBES)