BeijingAirblog.com

Wasn’t it nice? After the rains of Sunday 26th, we finally had a true blue sky day on Monday 27 August, when the API fell below 50. So open those windows, and switch off the airco! But this Tuesday morning the sky was grey again, and so i closed all the windows of our 10th floor apartment on the 4th ringroad again, and switched on our Blueair Air Purifier, a handsome machine we got a couple of months ago at the Pacific on Gongtibeilu. Does it work? Well, it makes some noise and produces some wind; for the rest we’ll have to trust the Swedish design (made in China). It says “ideal for rooms up to 200ft2/19m3″ but i hope that’s an understatement. Strange idea that we better stay at home to get some fresh air.

Have to mention that although the API for Beijing on 27 August was still higher than all the nearby cities of Tianjin, Shijiazhuang, Qinhuangdao, Datong, Taiyuan. We hadn’t had a cleaner day since 2 August.

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..

“Level two is a good enough standard for athletic competition,” said Yu Xianoxuan, environmental director of the Beijing Olympic Organising Committee. “If we had not had the traffic controls we could not have maintained this level because the temperature and humidity were very high. So we can see the restrictions worked.”

Level 2 refers to an API between 51 and 100. SEPA data show that API was 115 on 16 August which is level 3, and went down to the 90s over the 3 next days during the experiment. Not so sure the IOC will be happy with PM10 values of close to 0.150 mg/m3 which corresponds to API 100. SEPA also had this article from Xinhua. IHT had some doubts about the success.

Observations from this graph:

1. On 16 August, the day before the experiment began, the API was over 100 (level 3) but it went down below 100 for the next 3 days (level 2) although staying very close to 100.
2. The dip on 17 August could also be a result of regional effects, because we see the same dip in Tianjin where no experiment took place as far as i know.
3. On 20 August, the last day of the experiment, SEPA did not report API values for any of the 84 cities except Shijiazhuang (the magic number 88) - this was the first time ever this year that data went missing, and what a strange coincidence that it is right on this day..
4. The first day after the experiment, 21 August, the API was again over 100 and a simple interpolation suggests the value for 20 August could be around 105 which would have been quite a disappointing result on the fourth day of the experiment.

SEPA reports that this exercise was part of the Olympic Air Quality Guarantee Scheme which also includes controls on coal burning, industrial emissions, vehicle emissions, and raised dust. The interviewed official states that vehicles are the biggest emitters of the fine dust that creates Beijing’s air pollution, so that’s why this effort focussed on cars.

For 8 August 2007 the SEPA website showed a pollution index of 88, which might look nice in the run-up to the 8-crazy Olympics, but the authorities had probably hoped to see a lower value. Among all those stories about cloud-seeding, did the authorities manage to improve the air quality for the recent event on 8 August? Let’s have a look at the API around that date (original SEPA data).

Observations from this graph:

• Over this period, Beijing’s air was worse than Tianjin and Shijiazhuang (nearby cities - also see ‘local vs. regional’).
• The peak around 5-6 August appears in the 3 cities, but Beijing had no peak on 9 August while Tianjin and Shijiazhuang both had a one day peak - successful cloud-seeding in Beijing?
• Beijing has a remarkable downward trend until 13 August, and briefly becomes cleaner than Tianjin and Shijiazhuang - well done, or just a stroke of good luck?