大象传媒

Being exposed to air pollution over a long period of time can harm intelligence, a new study finds.

One of its authors, Dr Xi Chen from Yale School of Public Health, said: "Exposure to air pollution affects people's cognitive skills and ability not only in the short-term, but also in the long-term".

Over four years, the maths and verbal skills of some 20,000 people in China were monitored.

Researchers believe the results have global relevance, with more than 80% of the world's urban population breathing unsafe levels of air pollution.

(Image: A cyclist wearing an anti-pollution mask on London's Oxford Street. Credit: 大象传媒).