When US cyclists arrived in face masks yesterday, the International Olympic Committee chimed in again, echoing Beijing officials' insistence that there is nothing to fear when it comes to pollution.
"They were overly cautious," said a USOC spokesperson said of the cyclists, adding they regretted the action. The athletes were scolded by a US official for making a political statement and wrote a letter of apology. But it was the USOC's exercise physiologist that advised them to wear the masks. For their health. Not out of some unreasonable fear, or in an attempt to make a statement to China about its dirty skies.
That statement is already made many days by the skies themselves. 
If fear, among other things, is in the air, it may have something to do with the way the foreign media has covered the pollution issue ad nauseum.
But the media coverage aside, and despite the serious measures to take cars off the roads and close factories, the air can be nauseating. When I was out on the pale white moonscape of the Olympic green on Monday, my throat had the particular tickle of particulates. It wasn't just the intense heat. And I wasn't even running the 10,000 meter. Ditto for yesterday and today.
Yesterday, Arne Ljungqvist, chairman of the IOC's medical commission, said, "The mist in the air that we see [around the Olympic green] [...] is not a feature of pollution primarily but a feature of evaporation and humidity. We do have a communication problem here."
It seems we do have a communication problem here.
Adding to the smog -- and, perhaps unexpectedly, the negative media coverage -- are the government's feverish attempts, apparently parroted by the IOC, to convince everyone there is nothing to see here.
The fact is, depending on the haze, there can actually be nothing to see here. From the national stadium on Monday, the city seemed to have vanished in a luminous veil of white haze.
According to the handful of men on the street I asked, the problem wasn't pollution. "It's just the weather, heavy humidity. The government's made sure the city's not polluted for the Games," said a trash collector.
But according to Beijing's own measurements for the day, the concentration of PM10 dust was 269 micrograms per cubic meter, which is 168% above the WHO standard for short-term exposure.
Beijing's not been the most trustworthy source of pollution data. Steve Andrews, an environmental consultant who left Beijing last year for fear of reprisal, demonstrated in the Wall Street Journal earlier this year that the government had moved its monitoring stations to low traffic areas to make it look like pollution was decreasing.
He also pointed to the dubious "blue sky day" rating system, which gives that name to any day with an API reading of 100 or lower. Last year, the government beat its blue sky target due to a suspiciously high number of days that were exactly at 100.
(An API of 100 is still 6 times more polluted than the World Health Organization's long-term exposure standard for PM10 particulate matter, at a concentration of 20 micrograms/m3. Meanwhile, as one environmental engineer working in Beijing estimates, Beijing's average PM10 since July 20 has been 60% higher than that of the Los Angeles Games in 84, and 250% higher than Atlanta in 1996.)
But Ljungqvist said yesterday that this talk about smog was all a big misunderstanding. "Once the misconception has become sort of established in the minds of people, it's not that easy to get the right message through."
Recently, Xinhua quoted IOC official Gilbert Felli, who said "the low visibility doesn't necessarily mean the air quality is bad." (As BeijingAirBlog noted cheekily, in the video, Felli seems to have caught a cough.)
Despite official assurances, some are not taking their chances. Haile Gebrselassie, the world-record holder in the marathon, will not run the marathon because he is concerned about his health (he has exercise-induced asthma).
On the NewsHour this week, US Olympic mountain biker Adam Craig said the air in trials in Beijing last September led to bronchospasms. He and 40 other bikers dropped out before the race was over.
Again, Ljungqvist: "I would not discourage athletes from wearing protection devices if they are concerned, but I do not think it is necessary. I would not wear one whether I was an athlete or not."
That may be because, against serious pollution, masks probably won't do much.
Masks or no -- and each US athlete has one -- Craig and his teammates will only be in Beijing when they need to be. They've been training in South Korea. The track and field teams are in Dalian. Swimming and modern pentathon teams have decamped to Singapore.
After the Olympics, and after the cars return to the roads and the factories reopen, there will still be 17.4 million people living in Beijing. They can't all go take a breather in Kyoto.
As I wrote recently, Beijing may be sugar-coating and delaying its bad environmental news to pull off a "green" Olympics.
And the IOC doesn't seem to mind. As the IOC's medical official told the China Daily, Beijing is meeting the WHO air quality standards "in many aspects." Also:
"I am sure and confident that the air quality will not pose any major problem to the athletes and visitors...The WHO standards are not intended for temporary visitors... They are for permanent residents"
Comments BeijingAirBlog: "So all you athletes, officials, visitors, you don't have to worry, the air will be good enough for you. And the permanent residents, well, sorry, that's not the responsibility of the IOC. Thank you IOC for your contribution to China."
By not coming clean about the dirty air, officials from both Beijing and the IOC won't only continue to hurt the athletes, the credibility of the Olympics, and their reputations. Far more importantly, they'll be damaging the lungs of the 17 million people for whom Beijing is more than just a two-week long circus, but a place to live.