They have now apologized for emerging from Beijing airport with masks on, China Daily and Xinhua reported.

In a statement Wednesday, Michael Friedman, Sarah Hammer, Bobby Lea and Jennie Reed said, "We offer our sincere apologies to (the Beijing Olympics Organization Committee), the city of Beijing, and the people of China if our actions were in any way offensive," the reports said.

The four said their decision to wear masks was not intended to insult the committee or "countless others who have put forth a tremendous amount of effort to improve the air quality in Beijing," adding they planned to put the incident behind them and prepare for the competition.

Reed was quoted as saying, "The air is OK so far and it was just for travel."

Chinese authorities have taken extraordinary measures to fight perennial air pollution in Beijing and are happy with the results.

Arne Ljungqvist, head of the IOC medical commission, was quoted as saying the air quality would not affect the health of athletes and visitors during the Games.