The United States cycling team arrived at Beijing’s airport wearing black face masks. A spokesperson for the team said they weren’t doing as any kind of protest. “I don’t believe there was any statement trying to be made,” the spokesperson said.

Professor Arne Ljungqvist, chairman of the IOC medical commission, said he believed face masks were unnecessary for short-term visitors unless athletes had a prior medical condition and the air quality was particularly poor.

“I would not carry it [a face mask] myself whether I was an athlete or not,” he said. “I don’t see the need for it, honestly, unless there are very unfavourable days and you are sensitive to such situations.”

He added: “I know there are investigations going on in different laboratories providing different types of devices for protection in inferior air quality.

“Some may be better than others in their filter system. Whether they [the Americans] are carrying a new generation of mask I don’t know, but this is not a measure I would recommend unless you know you carry some sort of disorder that can be problematic under particular circumstances.”

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