BeijingAirblog.com

On 21 October the annual Beijing International Marathon (BIM) will be held for the 26th time (since 1981). Smart to organise this event in October, which has the best chances of low air pollution as mentioned in previous post. Its website says that 2 days before registration is closing, already 5000+ runners have signed up for the full 42km. The front page has a weather report and forecast, and warns not to forget a raincoat, but doesn’t tell anything about the air quality. Let’s have a look at the recents years to see what kind of pollution you may expect on this day.

I did not check on which exact dates the previous marathons where run, but if it was in this period in 2001, those runners must have noticed something. If we take the average API over those weeks, per year, it varies from 66 (2002) to 192 (2001), with the average being 106 for this week over the past 7 years. Last year the average for that week was 87. Anyway, these statistics show that it will most probably be around 100.

Then of course the question comes up: is it healthy to run 2+ hours in this air?

As mentioned before, the Beijing Olympic committee considers level 2 (API<100) acceptable for athletic competition, and SEPA says above 100 ‘The cardiac and respiratory system patients should reduce strength draining and outdoor activities’. Nevertheless I am quite sure the marathon will not be canceled even if the API reaches 150 on that day.

It would be interesing to get some feedback from marathon runners on this- please share your experiences with us.

Some interesting articles in the international press about this in relation to the Olympics:

• IHT writes that in past, athletes have stayed away from Olympic cities, in clean air, until 2 days before the competition, and some Olympic athletes are experimenting with face masks.
• The Scotsman reports the women’s marathon world record holder Paula Radcliffe is seeking advice from pollution experts how to prepare for Beijing2008, and cites a WHO doctor who in typical UN style blows hot and cold.
• Der Spiegel comments that it will be difficult to get ’Green Games’ as 50-70% of Beijing’s dust is generated in neighbouring provinces, and quotes a manager of the US Olympic team: ‘more than 20 percent of US athletes reacted to the smog in Athens with breathing difficulties. In Los Angeles, British runner Steve Ovett collapsed with respiratory problems after the 800-meter race. Ovett is convinced that pollution was the culprit. “Many suffered from the bad air, but hardly anyone said anything,” Ovett complained in an article in the scientific journal Nature.’
• The ClearAirInitiative website reports what happened when a marathon was run in Hong Kong with API of 149: a 53-year old runner died, 19 others collapsed. When authorities were asked why they did not cancel the event, they responded that at the time of the start, API was at an acceptable 100 (upper limit of level2). One expert however doubt the injuries/death had anything to do with the air pollution, and maintains that the benefits of exercising still outweight the risks of pollution.
• Not surprisingly, Hong Kong has a public debate on this issue, with Mr A J Hedley of the department of community medicine, University of Hong Kong, arguing that an API of 100 is by no means safe, and that there is fundamental damage at this level.

I put all the available SEPA data since 2000 (thanks Jacob) together to see if there is a trend in the standard deviation (measure for distribution around average) and on the below graph you can see that there is no real trend in average, mean, and standard deviation (note that data for 2000 and 2007 are incomplete).

I think the most important trend we can see from the SEPA dataset is the increase in ‘Clear Sky Days’ as mentioned in the previous post and illustrated by Jacob’s chart below; there is a clear shift from 3A to 2 which results in an increase of the sum of 1+2 = ‘Clear Sky Days’. That is pretty strange because the average is not moving. It means that there are relatively more days with API<100 but they are staying very close to the 100 value; that shows that this scale can be quite misleading; an API of 95 doesn't mean much better air for us than an API of 105, but it does count as a 'Clear Sky Day'.

Beijing is seeing its worst air pollution since 6 weeks, the API has hit 142 today. Maybe we should call the rainmakers at the Beijing Weather Modification Office (BWMO) and beg for some cloud seeding; rather have a bit of silver iodide in the air, than this thick smog. Weather modification employs 32000 people in China according to this ATonline article, and Beijing has about 135 trained farmers on standby for shooting the rainmaking artillery.

Let me mention here the excellent work Jacob from the Netherlands has done a couple of months ago when he was living in Beijing. He took the complete dataset available from SEPA for Beijing from 2001 to 2006 and applied some statistical analysis to it; original report in Dutch, which i happen to speak, so let me summarise some of his findings:

• the yearly average API for 2001 to 2006 is between 97 and 113 with no visible trend
• most of the heavy pollution days are in spring and to a lesser extent autumn (March and April being the worst)
• not many extreme values in summer, maybe because of rain effects
• the best chances for clean air (API below 50) are in October and November
• finally some good news; the Clear Sky Days are increasing, from 185 in 2001 to 241 in 2006 which beat the target of 238 for 2006 as this China Daily article reports- although we have to realise that a Clear Sky Day is defined as level 1+2 meaning an API below 100- as you could see this weekend, it is quite a stretch to call a API 90 day ‘clear sky’..

The current year-to-date average for 2007 is 99.6 so that is not better than the recent years, and also not worse. By this measure, the pollution level in Beijing is stable. 

According to the same China Daily article, Beijing’s target is 245 Clear Sky Days in 2007 - until now we have had 16 level1 days (API<50) and 152 level2 days (API between 50 and 100) so that means 168 ‘Clear Sky Days’ so far, resulting in a rate of 67%. Miraculously this is also exactly the above target rate of 245/365. Let’s hope this means the authorities are managing to reduce the actual pollution rather than massaging the daily measurement values.

In the above graph of the API in Beijing for this year you can see that there were only 4 days with API above 200 vs 5 to 24 such days in the recent years, which may mean the most extreme pollution is not occuring as often as in the past. However, the average remains around 100- it would be interesting to do some Gauss analysis on these data to see the evolution in its standard deviation- anybody?

While Beijing’s API has reached 100 again today, i found this inspiring IHT article about Bangkok while i discovered the Ecohutong blog. It gives me hope that a city can actually clean up its air by good policy and implementation. No doubt the Chinese authorities are looking at the Bangkok example as well, but they are of course heavily constraint by the Harmonious Society policy- how to provide a soft landing for all those individuals and companies whose business depends on their heavily polluting trucks, 3wheelers and minibuses? As far as i know, passenger car engines have to comply with EURO III since last year, but trucks&buses that are actually working 24/7 are still on inferior emission standards. And IHT also mentions the coal-fired power plants as the big polluters - natural gas would be much cleaner. And of course in China the oil/gas and car industries that would suffer from new standards are linked to the government. Imagine suing the Beijing public transport authority, as the former governor of Bangkok did in his city…

Anyway, the IHT article says the Bangkok’s PM10 has dropped 47% over the last decade, from 81 to 43 which is really amazing. In Beijing we only had 1 day in August (2nd) which was lower than 43 (42 actually) (note: in the range 0-50 API and PM10 are identical). A long way to go, and it’s clear that we will need more than even/uneven driving days experiments to get there.

Bangkok Pollution Control Department runs an clear&informative website with daily detailed statistics, showing for example today an Air Quality Index (AQI) of maximum 51 (see picture below). How/where it is measured in Beijing, i have found no clue on the SEPA website; if anybody knows, please comment.

And i made a quick comparison graph of the air pollution levels in Beijing vs. Bangkok from the start of August, no comment needed. In fact the API and AQI are not 100% equivalent and you can see here, but it seems that the AQI is even more strict than the API (100 represents PM10 of 120 micrograms/m3 vs 150 micrograms/m3 in Beijing).