中国空气中缺少灰尘反而使污染更严重?

Airborne dust is normally seen as an environmental problem, but the lack of it is making air pollution over China considerably worse.

虽然空气中的灰尘通常会被视为一个环境问题，但缺乏灰尘反而会对中国的空气污染造成相当严重的影响。

A new study suggests less dust means more solar radiation hits the land surface, which reduces wind speed. That lack of wind in turn leads to an accumulation of air pollution over heavily populated parts of China.

一项最新研究表明，较少的灰尘意味着更多的太阳辐射到达地面，这降低了风速。而风力不足会转而导致中国人口稠密地区空气污染的积聚。

The researchers found that reduced dust levels cause a 13% increase in human-made pollution in the region.

研究人员发现，由于空气中灰尘减少，导致人为因素引发的空气污染上升了13%。

Hundreds of millions of people across China continue to be impacted by air pollution from factories and coal-fired power plants. Studies suggest that the dirty air contributes to 1.6 million deaths a year, about 17% of all mortalities.

全国数以万计的人们将继续受到工厂和燃煤电厂所造成的空气污染的影响。研究指出，中国每年有160万人死于污浊空气引发的疾病，约占死亡人口总数的17%。

But this new research says that the human-induced pollution is being made worse or better by naturally occurring dust that blows in from the Gobi desert.

但这项新的研究表明，戈壁的风沙对人为因素造成的空气污染可以起到调节作用。

Using models to simulate 150 years of wind and dust patterns in the region, the researchers found that the dust deflects significant amounts of sunlight.

通过模拟这一地区150年以来刮风以及灰尘样本进行分析，研究人员发现，灰尘对阳光能起到显著的散射作用。

Differences in the temperatures between land and sea cause the winds to blow. Without the dust, the land warms up more and that changes the temperature differential with the sea leading to weaker breezes - and more air pollution.

风的形成来自海洋和陆地之间的温差。如果没有灰尘，地面的温度就会更高，从而改变了陆地和海洋温差的比值，并导致了风力减弱，空气污染就更严重了。

"There are two dust sources. One is the Gobi and the other is the highlands of north-west China, but we found the Gobi had much more influence," said lead author Yang Yang, from the Pacific Northwest National Laboratory in Washington State, US.

来自美国华盛顿州太平洋西北国家实验室、该研究的首席作者杨阳表示：“灰尘来自两个地方。一个是戈壁、另一个是中国西北部的高原，但我们发现戈壁施加的影响更大。”

"Less dust in the atmosphere causes more solar radiation to reach the surface. It weakens the temperature difference between the land and the sea and impacts the circulation of the winds and causes a stagnation over eastern China and that causes an accumulation of air pollution."

“大气中由于缺乏灰尘，导致地面接收到更多阳光辐射，弱化了陆地和海洋的温差，并对气流循环产生影响。由此，中国东部地区的空气出现停滞状态，从而导致空气污染的积聚。”