Burning Issues in Air Pollution
(Beijing) -- Hidden beneath a recent debate on an air pollution study are questions on the limits of scientific research in China. Air pollution has become a major public health issue in the country, but barriers to research continue to overshadow information on its negative impacts.
A paper by researchers from the Massachusetts Institute of Technology, Tsinghua University, Peking University and Hebrew University found that the use of coal for heating among China's northerners led to a cut in life expectancy by at least five years in the 1990s compared to those in the south. The conclusion sparked uproar among government officials and researchers.
The findings, titled, "Evidence on the Impact of Sustained Exposure to Air Pollution on Life Expectancy from China's Huai River Policy," were published in the U.S. National Academy of Sciences' official journal.
According to the report, life expectancies are about 5.5 years lower in the north of China than in the south owing to an increased incidence of cardiorespiratory mortality. More generally, the analysis suggests that long-term exposure to an additional 100 micrograms per cubic meter of Total Suspended Particles (TSP) is associated with a reduction in life expectancy at birth of about 3 years.
Among the study's critics is Pan Xiaochuan, a professor at the School of Public Health at Peking University. Pan said that the actual effect of environmental pollution on human health is much more complex than that portrayed in the study.
Pan's own research into the risks of air pollution on human health has generated controversy. At the end of 2012, Pan headed a research report by the environmental NGO Greenpeace and Peking University's School of Public Health, Pan which found that an estimated 8,572 premature deaths occurred in four major Chinese cities that year due to high levels of PM2.5 particulate (smaller than 2.5 microns) pollution.
The fact that more than three decades of China's rapid economic development created sweeping environmental degradation has long been recognized. But for many years, there has been little government acknowledgment of linkages between environment-related health problems. Research in China has also been limited by restrictions on environmental and health statistics, in addition to a lack of support for funding such studies.
Price of Bad Air
Chen Yuyu, a professor at Applied Economics Department, Guanghua School of Management of Peking University and head researcher of the Huai River paper, told Caixin the study made innovative application of commonly-used economic tools. He said the study collected abundant official data and the pollution figures, included daily TSP concentration readings in 90 cities on both banks of the Huai River from 1981 to 2000. In addition, the researchers also adopted statistics from China's Disease Surveillance Program (DSP) as well as the mortality rate of all ages, life expectancy and deaths from cardiopulmonary disease in the surveyed cities from 1991 to 2000. The researchers also collected corresponding data of the latitudes, temperatures, urban infrastructure, household income and education levels for each city.
The paper was soon steamrolled by officials from China's Ministry of Environmental Protection (MEP). Just two days after its release, Liu Zhiquan, deputy director of the Department of Science, Technology and Standards of the MEP lambasted the findings in the report. "The conclusion is biased. With insufficient data, such a conclusion is not credible," Liu said.
Liu acknowledged that soot from heating systems in the north contains heavy metals, fine particles, sulfur dioxide and other substances that could be detrimental to human health. "But as for the impact on life expectancy, there is no concrete evidence. There has been considerable controversy over the numerical algorithms used by the international community which still require long-term observation," Liu said.
Liu said long-term field studies are needed to collect more evidence, combined with surveys on a large number of samples. He also revealed that the MEP is working with the newly reshuffled National Health and Family Planning Commission (NHFPC) on research to establish an exposure impact assessment system.
Pan said his research applied more widely-accepted methods within the international scientific community. He thinks the key problem in the study lies not with insufficient sampling data as cited by the MEP, but a lack of data on other factors such as nutritional intake, medical care quality and economic development.
The question of how to quantify the damage of the environmental pollution on human health has plagued researchers in China for years.
Ten years ago, research into environmental hazards was a nascent field in the country. But as the general public has become increasingly aware of environmental issues, interest in the area has seen explosive growth.
In 2007, the State Environmental Protection Administration (SEPA), the predecessor to the MEP, joined hands with the World Bank on a collaborative study to assess the risks of pollution to human health using PM10 as an indicator.
However, the Chinese version of this study has never been made public. Two experts who participated in the study confirmed under the condition of anonymity that the study found 350,000 to 400,000 premature deaths were caused as a result of air pollution each year during that period.
The Chinese Center for Disease Control and Prevention (CDC), affiliated to NHFPC, has also been trying to explore the potential damage of environmental pollution on human health in recent years.
Yang Gonghuan, deputy director of the center, spent nearly 10 years with her team trying to find out the relationship between water contamination of the Huai River and the incidence of gastrointestinal tumors.
Their research concluded that there was a correlation between water pollution and gastrointestinal cancer. However, in an interview with Caixin, Yang was cautious in elaborating on her findings. She said the decade-long study merely established a correlation between water pollution and cancer, but determining a direct causal relationship would require more study.
Pan was optimistic that environment-related health research programs would receive more funding in the future. But he added the greatest constraints were limits on public health statistics.
"Environmental data and mortality figures are supposed to be open to the general public, but in fact scientists put tremendous amount of effort into gaining access," said Pan.
Chen also cited a lack of transparency in official figures as a major barrier to research. "But we feel very lucky to get any data because even if a study has ample funding, it's the official data that is the most valuable," Chen said.
Staff reporter Liu Hongqiao contributed additional reporting
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