一项研究发现，与欧洲和北美的PM2.5相比，中国的PM2.5致命性要低得多。中国疾病预防控制中心专家周脉耕领导的这个研究团队提出，这是因为中国的空气污染源于从干旱地区吹来的大量天然尘土，而西方的污染主要来自工业。
Smog in Europe and North America could be more than 25 times more lethal than the average air pollution found in Chinese cities, a new study suggests.
一项最新研究发现，欧洲和北美的雾霾致命性可能比中国城市平均空气污染水平高出25倍以上。
In the largest ever study of its kind in the developing world, researchers tested the effects of air pollution on the health of people in 272 cities in China.
在这项有史以来针对发展中国家进行的最大规模的同类研究中，研究人员测试了中国272个城市里空气污染对人体健康的影响。
They found average annual exposure to fine particles, known as PM2.5, in those cities was more than five times higher than the level recommended by the World Health Organisation (WHO), according to a paper in theAmerican Journal of Respiratory and Critical Care Medicine.
研究人员发现，在这些城市中，人们的年均PM2.5接触量是世界卫生组织建议水平的5倍多。研究论文发表在《美国呼吸系统和重症护理医学杂志》上。
However they also discovered that it was much less likely to increase the death rate than PM2.5 in Europe and North America.
但研究人员也发现，与欧洲和北美的PM2.5相比，中国的PM2.5致命性要低得多。
The researchers, led by Dr Maigeng Zhou, of the Chinese Centre for Disease Control and Prevention, suggested this was because China is affected by large amounts of natural dust blown by the wind from arid areas, while most pollution in the West comes from industry.
中国疾病预防控制中心周脉耕博士领导的这个研究团队提出，这是因为中国的空气污染源于从干旱地区吹来的大量天然尘土，而西方的污染主要来自工业。
They found that for every increase of 10 micrograms of air pollution in a cubic metre of air, the mortality rate increased by 0.22 percent, discounting deaths from accidents.
他们发现，如果不考虑意外事故造成的死亡，中国每立方米空气里的污染物每增加10微克，死亡率就增加0.22%。
Professor Frank Kelly, an expert in environmental health at King’s College London, who was not involved in the study but has studied air pollution in China, toldThe Independent: “Those relative risks are considerably less than those seen in Europe and the US.
英国伦敦大学国王学院环境健康专家弗兰克-凯利教授告诉《独立报》记者：“这些相对的风险明显比欧洲和美国小得多。”凯利没有参与此项研究，但研究了中国的空气污染。
“For premature mortality [in Europe] we are working on a six percent increase per 10 micrograms.”
凯利说：“就（欧洲的）过早死亡率来看，每立方米空气污染物每增加10微克，死亡率将增加6%。”
That suggests air pollution in Europe is about 27 times more toxic than average air pollution in China.
这表明，欧洲空气污染的毒性约为中国的27倍。
However Professor Kelly said cities like Beijing, Shanghai and Hong Kong were likely to suffer from Western-style air pollution.
但是，凯利教授说，北京、上海和香港这样的城市可能也存在“西式”空气污染。
"The natural dust component there is not of the magnitude that it would dwarf the coal, biomass and fossil fuel signals,” he said.
“那儿空气中天然尘土的数量还不足以使煤炭、生物物质和化石燃料等因素相形见绌。”
“That [the lower mortality rate] may be true in certain cities whose pollution is not dominated by local power generation or major traffic congestion.”
他说：“在污染物主要不是来自当地电厂或严重交通拥堵的某些城市，（死亡率较低）可能是事实。”
Natural dust particles can cause physical damage to the lungs and trigger an asthma attack. Particles of carbon produced when fossil fuels are burned can lead to similar problems but they are also coated with toxic heavy metals, chemicals and volatile organic compounds.
天然粉尘可能使肺部受损，引发哮喘。燃烧化石燃料时产生的碳微粒可能导致类似问题，但它们外表还包裹着有毒的重金属、化学物质和挥发性有机物。
These are able to pass from the lungs into the blood stream where it is thought they cause further damage to the body.
这些物质可能从肺部进入血液，据称这会给身体造成进一步损害。
Areeba Hamid, an air pollution campaigner with environmental group Greenpeace, said: “Toxic air causes havoc to people’s health wherever in the world they live.
环境团体绿色和平组织的反空气污染活动家阿丽芭-哈米德说：“有毒空气给世界各地人们的健康造成严重损害。”
“We now know fumes from diesel vehicles are a lot more toxic than car companies claimed and this is a big cause of air pollution in Europe and North America.
“我们如今知道，柴油车排放的废气毒性比汽车公司宣称的要大得多，而这是欧洲和北美空气污染的一大原因。”
“These companies have a lot to answer for, but so far they’ve managed to avoid any real accountability.”
“这些公司要承担很大责任，但到目前为止它们都避免承担任何真正的责任。”
The study of cities in China found the average annual expose to PM2.5 was 56 micrograms per cubic metre, compared to the WHO guideline limit for safe air quality of 10 micrograms.
对中国城市的这项研究发现，PM2.5的年均接触量为每立方米56微克，而世界卫生组织的空气质量安全标准为每立方米10微克。
People who were older than 75, had less education or who lived in hotter places were more likely to die.
75岁以上、教育水平较低或生活在较热地区的人死亡风险更高。
It is thought people in warmer cities were more likely to spend time outside or leave their windows open, thereby breathing more polluted air, the researchers said.
研究人员说，在较热城市生活的人到户外去或开窗的时间可能更长，因此会吸入更多的污染空气。
They also speculated that less well educated people might have poorer access to health care or experience poorer environmental health conditions.
他们还推测说，教育水平较低的人享受医疗服务的机会较少，他们接触的环境卫生状况也较差。
