Archive for March, 2011

beijing’s february air pollution more than twice as bad as january’s

Tuesday, March 1st, 2011

In January of this year, Beijing experienced unprecedented air quality, with all 31 days being Blue Sky Days (“good” or “excellent” air quality). At the end of the month, Du Shaozhong, a Deputy Director at the Beijing EPB, claimed that this result was “far from one-off.” I disagreed, arguing that the sudden and dramatic reduction in air pollution in January could not reasonably be explained as simply the positive result of years of pollution control programs. (Although these programs have clearly had some impact, I think January’s outlier result was likely caused primarily by favorable meteorological conditions as opposed to changes in pollution sources.) Regardless, I noted that I’d be curious to see what happened in February, and what corresponding response – if any – the Beijing EPB offered.

Well, now February has passed, and the air quality results are in. Unfortunately, there is little to be “ebullient” about. There were just 18 Blue Sky Days in February (64%), and I calculated the average PM10 concentration over the month to be 144 ug/m^3. In addition to being well over twice as bad as January’s (during which the average PM10 concentration was just under 60 ug/m^3), this level is almost 50% worse than China’s own national ambient air quality standard, and over 7x worse than the WHO’s recommend annual limit.

The average was skewed by the four absolutely horrible air quality days from February 21-24, but even without considering those days, the average PM10 for the month was still 107 ug/m^3, above China’s standard and 5x worse than the WHO’s.

(As always, my data sources are MEP’s datacenter for API data, which I convert to PM10 concentration using formulas described here.)

I am still waiting for the Beijing EPB to issue their monthly air quality report, and will try to check in again once they do.