Heavier air pollution in the coal-burning north of China takes an average of three years off a person's lifespan, compared with residents of the country's southern provinces, a recent study has found.
Policies implemented by the ruling Chinese Communist Party backing widespread coal-burning for central heating "is unintentionally causing people in northern China to live 3.1 years less than people in the south due to air pollution concentrations that are 46 percent higher," a recent study published in the Proceedings of the National Academy of Sciences found.
The elevated mortality is entirely due to an increase in cardiorespiratory deaths, indicating that northern China's smog-filled winters are behind the phenomenon.
"Unveiling this important information helps build the case for policies that ultimately serve to improve the lives of the Chinese people and the lives of those globally who suffer from high levels of air pollution," study co-author Zhou Maigeng, deputy head of chronic and noncommunicable diseases at China's Center for Disease Control and Prevention, said in a statement.
Co-author Michael Greenstone, who heads the Energy Policy Institute at the University of Chicago, said particulates are "the greatest current environmental risk to human health, with the impact on life expectancy in many parts of the world similar to the effects of every man, woman, and child smoking cigarettes for several decades."
China's Huai River policy ensures that anyone living north of that river will have access to central heating powered by free coal, with no coal provided to its south.
Restrictive household registration and anti-migration policies ensure that the majority of the population stay in place for their lifetimes, enabling a clear link between greater air pollution and shorter life expectancy to be drawn, the study authors said.
"The study's unique design provides solutions to several challenges that have been difficult to solve," co-author Fan Maoyong, associate professor at Ball State University, said.
"The Huai River policy also provides a research design that can be used to explore a variety of other questions about the long-run consequences of exposure to high levels of pollution," Fan said.
Previous studies have been unable to measure the effects of exposure to high concentrations of air pollution on a fairly stable population over a long period of time, the authors said.
China has recently stepped up efforts to deal with its "airpocalypse" of brown smog that swathes much of the country in the winter months, and is in the process of switching its primary source of heating from coal-fired boilers to gas-fired or electric units, the study authors said.
The authors said that particulate air pollution in some of China's most polluted cities, such as Beijing, has "improved significantly" since.
"Our findings show that these changes will bring about significant health benefits for the Chinese people in the long run," co-author He Guojun of the Hong Kong University of Science and Technology said.
"If all of China were brought into compliance with its Class I standards for PM10 (40 μg/m^3), more than 3.7 billion life-years will be saved," He said.
But Xie Tian, professor at the University of South Carolina, said China's huge and wide-ranging environmental problems don't stem from a lack of good policies, but from vested interests at local level preventing their enforcement.
"Actually, Chinese environmental law is excellent, and it all looks great on paper," Xie told RFA. "But there is a widespread failure to enforce it, which is a major problem."
"Local governments don't regard environmental protection as important, and they fake the environmental pollution statistics."
"Companies issue backhanders to environmental protection officials, and carry on polluting as before," he said.
The study found that every additional 10 micrograms per cubic meter of PM10 particulate pollution reduces life expectancy by 0.6 years.
But there was no data reported for PM2.5 particles, which are small enough to get directly into the bloodstream.
The researchers are currently planning an air pollution index to enable some 4.5 billion people around the world to estimate how much longer they would live if they could only breathe cleaner air, Greenstone said.
Reported by Xi Wang for RFA's Mandarin Service. Translated and edited by Luisetta Mudie.