Article posted Thursday, November 6, 2014 2:32pm

From 1981 to 2001 China had a policy that denied people living along the south side of the Huai River free coal for the winter. In contrast, people living on the north side were provided with coal. Scientists took advantage of the opportunity to compare effects of airborne particulate material (APM), such as soot or other products of combustion, on the health of people living in the two regions. Statistical analyses of health records were adjusted to ensure the two groups were directly comparable. The results showed that north of the river, there was an increase in APMs and a discrete decrease in life expectancy of three years. Conclusions are that the source of the APMs was coal and that their presence in the atmosphere shortens life. (Chen et al, Proc. National Acad. Science, August 6, 2013; Science, April 18, 2014)