Outdoor air pollution contributes to the deaths of an estimated 1.6 million people in China every year, or about 4,400 people a day, according to a newly released scientific paper.
The paper maps the geographic sources of China's toxic air and concludes that much of the smog that routinely shrouds Beijing comes from emissions in a distant industrial zone, a finding that may complicate the government's efforts to clean up the capital city's air in time for the 2022 Winter Olympics.
The authors are members of Berkeley Earth, a research organization based in Berkeley, Calif., that uses statistical techniques to analyze environmental issues. The paper has been accepted for publication in the peer-reviewed scientific journal PLOS One, according to the organization.
According to the data presented in the paper, about three-eighths of the Chinese population breathe air that would be rated "unhealthy" by United States standards. The most dangerous of the pollutants studied were fine airborne particles less than 2.5 microns in diameter, which can find their way deep into human lungs, be absorbed into the bloodstream and cause a host of health problems, including asthma, strokes, lung cancer and heart attacks.
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The organization is well known for a study that reviewed the concerns of people who reject established climate science and found that the rise in global average temperatures has been caused "almost entirely" by human activity.
The researchers used similar statistical methods to assess Chinese air pollution. They analyzed four months' worth of hourly readings taken at 1,500 ground stations in mainland China, Taiwan and other places in the region, including South Korea. The group said it was publishing the raw data so other researchers could use it to perform their own studies.
Berkeley Earth's analysis is consistent with earlier indications that China has not been able to successfully tackle its air pollution problems.
Greenpeace East Asia found in April that, of 360 cities in China, more than 90 percent failed to meet national air quality standards in the first three months of 2015.
The Berkeley Earth paper's findings present data saying that air pollution contributes to 17 percent of all deaths in the nation each year. The group says its mortality estimates are based on a World Health Organization framework for projecting death rates from five diseases known to be associated with exposure to various levels of fine-particulate pollution. The authors calculate that the annual toll is 95 percent likely to fall between 700,000 and 2.2 million deaths, and their estimate of 1.6 million a year is the midpoint of that range.
The Chinese government is sensitive about public data showing that air pollution is killing its citizens, or even allusions to such a conclusion. Though the authorities have gradually permitted greater public access to air quality readings, censors routinely purge Chinese websites and social media channels of information that the ruling Communist Party worries might provoke popular unrest. In March, after a lengthy documentary video about the health effects of air pollution circulated widely online, the party's central propaganda department ordered Chinese websites to delete it.