Pollution was not a factor on the opening day of Olympic competition in Beijing, Games officials said on a hazy and sticky Saturday.
"The levels are well within normal limits," International Olympic Committee spokeswoman Giselle Davies told a news conference, dpa reported.
Local organizing committee vice-president Wang Wei struck a similar line, saying: "We are quite confident that air quality will have no negative impact on the athletes."
China has taken big steps to fight Beijing's notorious pollution, closing down factories during the Games and moving others to different regions. Traffic restrictions are also partly aimed at making the air better in the Chinese capital.
Saturday's figures were not yet available, but organizers said that the air pollution index stood at 94 on Friday, below the limit of 100.