With sensitivities running high among Beijing officials who promised a Green Olympics, including clear skies, any suggestion that the air quality is actually less than clear has caused some hurt feelings among the hosts.

It’s a prickly issue, because some athletes are limiting their time in Beijing, while four American track cyclists arrived yesterday in black face masks.

In fact, weather conditions have run the gamut in the final weeks ahead of Friday’s opening ceremony — from delightful to downright awful — and that has revealed a sharp contrast in the terms many foreign journalists use and those used by Chinese officials and media, who cite a wide range of terms but generally avoid admitting there’s actually any pollution.

These include terms translated as “fog”, “haze”, “static breeze”, “adverse weather”, “sauna” conditions, “temperature inversion”, “cloudy days”, “dark days” and of course “blue sky days”.

“Just like in the shower you cannot see the person across from you, but there is no pollution,” Du Shaozhong, deputy director of Beijing’s municipal environmental protection bureau, reassured journalists at a news conference last week. Days before he said “cloudy days, foggy days do not necessarily result from pollution in the air.”

Some editors prefer to let pictures tell the story, but Du had a ready reply for that too: “Pictures cannot reflect reality,” the Xinhua news agency quoted him as saying in a report. “They are not accurate. I really urge you not to use photos to base your assessment of air quality.”

PHOTO: U.S. track cyclist Michael Friedman arrives at Beijing airport wearing a mask, August 5, 2008. REUTERS/Issei Kato