Restrictions on Beijing motorists during a three-day period last November significantly reduced smog and airborne pollutants.
Chinese officials, in what was viewed as a rehearsal for the 2008 Summer Olympics, imposed restrictions that resulted in approximately 800,000 of Beijing's 2.8 million vehicles being taken off the road. The result, according to a U.S. study, was a 30 percent reduction in the city's traffic volume and a resulting 40 percent decrease in nitrous oxide emissions.
Harvard University researchers Michael McElroy, Yuxuan Wang and K. Folkert Boersma used data from the National Aeronautics and Space Administration's Aura satellite to assess the drop in emissions.
"I don't think a proper analysis has ever been made before of such a remarkable shift of environmental policy in such a short period of time," said McElroy, a professor of environmental studies.
China's restrictions on Beijing drivers coincided with the Forum on China-Africa Cooperation, held in Beijing Nov. 4-6.
Wang, a Harvard postdoctoral fellow, said, "We expected a drop in nitrogen emissions, but not to this extent, and after only a short period of time."
The scientists detail their research in the current issue of the journal Geophysical Research Letters.
Copyright 2007 by United Press International
Explore further: China's struggle for water security