Beijing Air is a new blog that has set out to “bring together some information on the air quality in Beijing, mainly to answer the question: how wise is it to live in Beijing, if you have other options? Can you raise your kids in this city without affecting their chances of a healthy life?”
It’s particularly timely, because the Beijing city government just concluded an experiment: from August 17 to 20, cars with even-numbered licensed plates could only be used on the 18th and 20th, with odd-numbered plates restricted to driving on the odd-numbered days.
The intention was to reduce air pollution and traffic congestion, and to give the city more information about how to ensure clear skies and smooth traffic during the Olympics next year. The city authorities declared the experiment a success: the image above shows a text message sent from the city government to mobile phone users in Beijing that says:
Citizen friends: the four day environment traffic experiment has been successfully completed. We wholeheartedly thank you for your contribution to improving the capital’s air quality and preparation for the Olympics — Beijing Party Committee and Beijing Government
As the Beijing Air blog points out, “4 days of reduced traffic experiment in Beijing shows no improvement in air quality, although the authorities suggest it would have been worse without the restrictions, so they claim the experiment was successful nevertheless.”
Well, how was the air quality during the four day experiment?
The data for Beijing’s air quality below is from China’s environmental protection agency SEPA, and shows the ‘pollution index’ or API which stands for airborne particulate index. Anything up to 100 is not a problem (according top SEPA), 101 to 200 is ‘slightly’ to ‘lightly’ polluted’ and not a serious problem. When the API count exceeds 200, SEPA says that “The symptoms of the cardiac and lung disease patients aggravate remarkably, and the exercise endurance drop lower. The healthy crowds popularly appear some symptoms.”
Looking at August 10 to 15 on the chart, the API numbers are all under 100. For some reason, the index shot up to 115 the day before the traffic experiments started, and returned to 116 on the 21st, the day after the experiment ended. So it does indeed seem that the reduction in the cars on the road helped to keep the pollution at acceptable levels during the experiment.
But if you look at the area highlighted in red on the graph above, you’ll notice that there are no numbers given for Monday August 20.
Monday was in fact a bad air day in Beijing. Why are the numbers for that day missing?