Scientists at the Department of Energy's Pacific Northwest National Laboratory say rain just at the beginning of the Olympics and wind during the event likely contributed about half of the effort needed to clean up the skies.
Emission controls China put in place before and during the August Olympics included restricted driving, temporarily halting pollution-producing manufacturing and power plants, and even relocating heavy polluting industries in preparation for the games.
That resulted in about half the actual emission reductions, researchers said, with weather a strong helping factor.
"In addition to the emission controls, the weather was very important in reducing pollution. You can see the rain washing pollution out of the sky and wind transporting it away from the area" in computer models, atmospheric chemist Xiaohong Liu said in a PPNL release Tuesday.
"They got very lucky. There were strong storms right before the Olympics," he said.