BEIJING'S air was cleaner during last summer's Olympic games, but pollution levels were still much higher than at other recent Olympic venues.
Despite a clean-up campaign, athletes in Beijing faced pollution levels that were up to 3.5 times higher than in Athens, Atlanta and Sydney, according to a study published in the journal Environmental Science and Technology.
The pollution often
exceeded what the World Health Organisation considers safe.
The joint American-Chinese study – the first major one published on air pollution during the Olympics – also found the weather, and not the Chinese government's strict controls imposed in the run-up to the games, played the largest role in clearing the air.
Scientists from Oregon State University and Peking University looked at Beijing's worst air pollutant – tiny dust particles known as particulate matter – over an eight-week period before, during and after the games.
China poured some $20 billion (£12bn) into "greening" the city after it won the bid in 2001, including doubling the number of subway lines, refitting factories with cleaner technology and building urban parks.
Government officials also imposed drastic clean-up measures just before the games in mid-July, including pulling half the city's 3.3 million vehicles off the roads, halting most construction and shutting down dozens of factories.
Staci Simonich, an associate professor of chemistry and toxicology at Oregon State University, said: "It was a giant experiment and a noble effort. But in the end, the extra added measures didn't help reduce (polution] concentration as much as had been expected."
