"Beijing's air quality poses no risk to athletes' health, Jacques Rogge, the president of the International Olympic Committee, has told reporters."

"Mr Rogge urged reporters to distinguish between fog and pollution"

""The fog, you see, is based on the basis of humidity and heat. It does not mean that this fog is the same as pollution," he said."

http://news.bbc.co.uk/2/hi/asia-pacific/7546872.stm