Lack of Dust Making China's Air More Toxic

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

A new study, published in the journal Nature Communications, suggests less dust means more solar radiation hits the land surface, which reduces wind speed, BBC News reported.

That lack of wind in turn leads to an accumulation of air pollution over heavily populated parts of China.

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

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.

But this new research says human-induced pollution is being made worse or better by naturally occurring dust that blows in from the Gobi Desert. Without it, more heat from the Sun hits the land. Differences in the temperatures between land and sea cause the winds to blow, according to lead author Yang Yang, from the Pacific Northwest National Laboratory in Washington State, USA.

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. One of the key lessons from this study is that the absence of dusty conditions could mean the air you are breathing is worse for you, not better.

"If it's not a dusty year, you may be happy and spending more time outdoors because you don't have this dust in the way, but you are actually going out to spend more time in more toxic air," said Prof. Lynn Russell from the Scripps Institution of Oceanography in California.