Wednesday, July 1, 2009

china daily features online survey on beijing's air quality monitoring

When I wrote yesterday about the China Daily article on the discrepancies between China's officially reported air quality data and the US Embassy's BeijingAir Twitter feed, I didn't realize that the China Daily story appeared on the site's home page along with an incredibly direct web survey:

Web surveys are, of course, not scientific or reliable at all, but nonetheless here's a screen capture of the results as of around 11am this morning:

It's difficult to imagine such a critical survey happening on a Chinese-language state media site, but I will keep an eye out for anything comparable.

Lastly, for the record, there are several mistakes in the China Daily story that I should point out. Three are in this sentence alone: "A blue-sky day is when the city's air pollution index, the level of five airborne pollutants, falls below 100, indicating that no health implications exist."

First, MEP makes no claim that blue-sky days have "no health implications," only that those days have the poorly-defined "excellent" or "good" air quality. Air quality on blue-sky days can certainly have negative health implications, especially for sensitive populations in the short term and for everyone in the long term. What MEP calls "good," the US EPA calls "moderate," saying, "Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution."

Second, the air pollution index only covers three pollutants, not five. I'm not sure how China Daily made this mistake, because later in the article they describe the number correctly ("the current evaluation system uses only three indices: Sulfur dioxide, carbon dioxide and PM 10s"), although they get the pollutants wrong. (The three are sulfur dioxide, nitrogen dioxide, and PM10.)

Third, this is minor, but a blue-sky day is a day in which the API is technically 100 or below, not below 100.

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