Shockingly little has been published in the peer-reviewed literature about the air pollution in China, although there has been plenty of press coverage. I talked a little bit about the US Embassy twitter data and how fires polluted the air over Beijing*. The health impacts of the exposure of humans to sustained levels of unhealthy or hazardous air pollution levels is widely expected to increase mortality rates due to cardiorespiratory failure and increased instances of cancer. The question then is raised: What hard evidence exists that proves this hypothesis? Modeling studies seemed like they would have to suffice. Until now.
Researchers from China, Israel, and the USA just published what I would call a very important study that concludes that elevated particle pollution in Northern China compared to Southern China has reduced life expectancy by 5.5 years. They took advantage of a dataset that emerged as a result of a Chinese policy employed from 1950-1980 that provided free coal for heating for everyone living north of the Huai River that runs right through the center of China and shown as the black line in the figure below.What they found was that particle pollution concentrations were 55% higher in Northern China due to the availability of free coal. This strong and significant difference between the north and south as a result of the Huai River policy (as the researchers call it) set up an experimental control scenario on a large enough scale (population wise) that the statistics were robust. The statistical model combined the particle concentration difference with proximity to the Huai River, detailed mortality statistics from a program in China called the Disease Surveillance Points (DSPs), and a number of other possible factors that may influence mortality to prove with high confidence that their results were robust. The life expectancy of the Chinese citizens north of the Huai River (which includes Beijing, Lanzhou, and Xian) is on average 5.5 years less than those of citizens living south of the Huai River. The decrease in life expectancy, the research shows, was almost entirely attributable to the 55% increase in particle pollution concentrations. The paper is worth reading, especially given the current state of Chinese air quality referred to above.