It looks as if the return of Beijing's pollution could be a problem for Olympic athletes indoors as well as outdoors.
The Australian swimmers went to the so-called Water Cube for the first time only to find the smog that blanketed the Olympic city yesterday infiltrating the space-age aquatic centre.
It had been thought the indoor pool would safeguard the swimmers from problems such as asthma, which is known to afflict world record holders Grant Hackett, Libby Trickett and Jess Schipper
But head coach Alan Thompson says there's a noticeable haze inside the 17,000-seat swimming venue too.
The unique venue has been sold out for months and the setting is expected to be one of the highlights of the Games.
Meanwhile American superstar Michael Phelps touched down in Beijing but managed to escape a large media throng.