The number of cars in China doubled between 1995 and 2002

SciDev.Net / D. Dickson

Satellite data has shown that levels of a key air pollutant above the Chinese capital Beijing are much higher than previously thought. And they are still rising, say researchers whose findings are published today in Nature.

The research contradicts previous estimates that calculated emissions of nitrogen dioxide according to the amount of fuel burned on the ground.

These calculations suggested that nitrogen dioxide levels were reaching a plateau, possibly in part because of the government's attempts to reduce air pollution by introducing measures such as clean coal technologies.

Instead, data from two satellites indicate that nitrogen dioxide levels between ground level and ten kilometres above Beijing have risen by 50 per cent during the past decade, and that the build-up is accelerating.

The authors suggest this could be due to the greater number of cars on the streets of Beijing. The number of cars in China doubled between 1995 and 2002.

Link to full news article in Nature

Link to full research paper in Nature

Reference: Nature 437, 129 (2005)