Air pollution causes people in northern China to live an average of 5.5 years shorter than their southern counterparts, according to a study released on Monday, which claims to show in unprecedented detail the link between air pollution and life expectancy.
High levels of air pollution in northern China — much of it caused by an over-reliance on burning coal for heat — will cause 500 million people to lose an aggregate 2.5 billion years from their lives, the authors predict in the study, published in the Proceedings of the National Academy of Sciences journal.
The geographic disparity can be traced back to China’s Huai River policy, which, since it was implemented between 1950 and 1980, has granted free wintertime heating to people living north of the river, a widely acknowledged dividing line between northern and southern China. Much of that heating comes from the combustion of coal, significantly impacting the region’s air quality.
“Using data covering an unusually long timespan — from 1981 through 2000 — the researchers found that air pollution was about 55% higher north of the river than south of it,” the Massachusetts Institute of Technology (MIT) Energy Initiative said in a statement.
“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 variation to be attributable to cardiorespiratory illness, and not to other causes of death,” the statement said.
The researchers, based in Israel, Beijing and MIT, gauged the region’s air quality according to the established metric of “total suspended particulates [TSP],” representing the concentration of certain airborne particles per cubic meter of air.
The study concluded that long-term exposure to air containing 100 micrograms of TSP per cubic meter “is associated with a reduction in life expectancy at birth of about 3.0 years.”
Air pollution has been the subject of widespread public outrage in China since January, when Beijing’s air quality index (AQI) — a similar metric to TSP — regularly exceeded 500, the scale’s maximum reading, for weeks on end. On Jan. 12, Beijing’s AQI hit a record 755, 30 times higher than levels deemed safe by the WHO.