每日英语：Air Pollution From Coal Use Cuts Lifespans in China, Study Shows

Air pollution from coal combustion likely cut life expectancy in parts of China by more than five years during the 1990s, a study has found, adding weight to increasing public demands for Beijing to clean up the environment.

Lifespan：寿命　　　　combustion：燃烧，氧化　　　　

The effects on human health from China's high levels of pollution are likely worse than experts had thought, according to a new study by researchers at the Massachusetts Institute of Technology and three other universities. The report released Monday looks at life expectancy in parts of China, taking into account the amount of coal burned and government policy on coal use.

China has grappled with persistent air pollution from its rapid economic growth, raising concern about the impact on the nation's health. While the country has made progress in recent years on tackling some toxins, such as sulfur dioxide, air pollution today remains at 'extraordinarily high levels,' said MIT's Michael Greenstone, one of the authors of the study.

toxins：毒素，毒物　　　　sulfur dioxide：二氧化硫　　　　

Last month, China unveiled a series of measures aimed at getting its pollution problem under control. The government set a target for reducing emission intensity in key industries by 30% by the end of 2017. President Xi Jinping also signaled that local officials will need to do a better job of keeping pollution low in their jurisdictions. 'The government takes this problem very seriously,' said Tang Dagang, director of the Chinese Ministry of Environmental Protection's Vehicle Emission Control Center. 'These measures are much stricter and more specific than in the past.'

jurisdictions：行政辖区　　　　

The research by MIT, Peking University, Tsinghua University and Hebrew University of Jerusalem was facilitated by a policy, derived in the Mao era and since abandoned, under which the government distributed free coal to heat homes and offices in northern China, but not in the south. The government used the Huai River in central China as a dividing line, giving the study clear physical parameters for comparison.

Life expectancy across north and south China was broadly similar, the researchers found. But they discovered a sharp difference between the area just north of the river and that immediately to the south, with life expectancy just north of the Huai 5½ years shorter. That finding ran counter to predicted life-expectancy based on incomes and demographic factors, they said.

The geographic pattern makes it less likely the contrast in life expectancy was caused by differences in income or access to health care, the study argues. Indeed, it cites death records showing mortality from cardio-respiratory disease accounted for that difference. Air pollution is a contributing factor to cardio-respiratory illness.

mortality：死亡率　　　　respiratory：呼吸的　　　　

The paper focused on the effects of soot, smoke and other airborne particles that tend to localize, but not on gases such as nitrous oxides and sulfur dioxide, which can easily waft across the country.

Researchers were helped by another Mao-era government policy, also now effectively discontinued, restricting movement of people from one part of the country to another, so most people studied had likely spent their lives in the same region.

China is the world's largest consumer of coal and continues to subsidize coal production, ultimately allowing many buildings with coal-fired furnaces to provide occupants cheap central heating, although the government is looking at ways to give the market a bigger role in setting energy prices.

Still, the study shows the potential hazards of governments subsidizing consumer fuel use. 'This was a very well-intentioned policy to provide heat for people in the winter, but we're uncovering the unintended consequences,' said MIT's Mr. Greenstone.

Another of the researchers, Hongbin Li of Tsinghua University in Beijing, contributes occasional opinion articles to The Wall Street Journal's Chinese-language edition.

Meantime, the effects of high concentrations of pollutants on humans still aren't well understood. Most studies on air pollution so far have looked at developed countries where skies are relatively clean in comparison. 'The problem is this has been studied in London and Los Angeles and cities where the overall levels are much lower than Beijing,' said Carter Brandon, a former manager of the World Bank's environment programs in China, who wasn't involved with the study.

Though China has made progress in tackling certain forms of pollution, such as sulfur dioxide, levels of airborne particles remain many times higher than in the West. On Monday, the New York Department of Environmental Conservation's Air Quality Index forecast for New York City was 65. In contrast, the U.S. embassy in Beijing reported an AQI of 164, and earlier this year the reading topped 700. A higher index reading denotes more pollution.