New research suggests that China's impressive feat of cutting Beijing's pollution up to 50 percent for the 2008 Summer Olympics had some help from Mother Nature. Rain just at the beginning and wind during the Olympics likely contributed about half of the effort needed to clean up the skies, scientists found. The results also suggest emission controls need to be more widely implemented than in 2008 if pollution levels are to be reduced permanently.

Liu and colleague Chun Zhao at PNNL and at the Chinese Academy of Sciences in Beijing took advantage of the emission controls China put into play before and during the August Olympics to study the relative contributions of both planning and nature. Chinese officials restricted driving, temporarily halted pollution-producing manufacturing and power plants, and even relocated heavy polluting industries in preparation for the games.