08/05/2008 05:12 am ET Updated Dec 06, 2017

In Last Ditch Effort for Clean Olympic Air, Beijing May Ban 90 Percent of Cars

Beijing's big air cleanse began a week ago, and the results are clear (or not, as it were): closing some factories and taking half its cars off the roads has not kept away the smog.

Last week officials downplayed concerns but after a depressing weekend of soupy air and low visibility, the government is now considering what China Daily calls an "emergency green plan" for the Olympics: 90 per cent of Beijing's 3.3 million vehicles could be kept off the roads and more factories could face temporary closure.

For example, instead of limiting cars based on whether their license plate ended in an odd or even number, as the current restriction stipulates, the Beijing government could limit plates to those that end in the current date.

The announcement came on the same day that Greenpeace issued a report on Beijing's greening operations, and said the smog would be dangerous for athletes. To qualify as a "blue sky day," which Beijing says is safe for athletes, the Air Pollution Index, which typically measures small particulate matter, or PM10, must be below 101.

For the past few days, as you can see in the chart below, it's been higher than that; today it was 113. (Strangely, at the moment the Ministry of Environmental Protection's site"s latest data is from last week, but more recent data can be found at this site and at the Wall Street Journal's widget). But even if Beijing can reach 100 and below for the big event -- and it will do whatever it can to get there -- even that won't be enough.

Courtesy BeijingAirBlog

Beijing's pollution monitoring system has come under fire for being misleading, whether it's because of its nomenclature ("blue sky day" doesn't mean blue skies, and "fog" or "haze" doesn't mean smog) or the location of its sampling stations. But calling Beijing's average API of 100 acceptable seems just egregiously wrong. That's 6.5 times the World Health Organization guideline for long term exposure. As the WHO wrote (pdf) in 2005:

A PM10 concentration of 150 μg/m3 [equal to an API of 100] would be expected to translate into roughly a 5% increase in daily mortality, an impact that would be of significant concern, and one for which immediate mitigation actions would be recommended.

And as a public health professor noted at BeijingAirBlog, "anything above Chinese API=50 is very unhealthy. Even if it is at API=50, that is still more than double New York City usual levels, so that is not acceptable either. They really need to get the API down to 25 or below to call the air acceptable for Olympic competition."

Because athletes will be ingesting more air than an average person during endurance events, the hazard for them is even greater. The IOC chief said that some outdoor events may need to be rescheudled, and today Australia's Olympic Committee said today that its athletes would be allowed to drop out of events if they were concerned about air quality.

Though official reports last week said that the car measures had reduced emissions by 20 percent, Beijing's suffers chronically from its location, stuck inside a "bowl" formed by mountains to the north that help to trap pollution over the city.

What Beijing needs now for its grand air experiment to look like a success are rainfalls and strong clean winds. The former is something the government already has some control over, and which it expects more of in the coming days. But winds, which are more important for dispersing smog, are one of the factors for which Beijing has no control. Not yet at least.

Read more HuffPost coverage of the 2008 Beijing Olympic Games