Sunday, June 23, 2013

Deceived by the Sky

This morning I noticed that the air seemed relatively clear--meaning I didn't notice a haze in front of buildings across the street and the sky had a spirit-lifting bluish color.

The sky in Beijing around 9:40 a.m.

I assumed this meant it was at least a semi-decent air day. So I was surprised when I later looked at the Beijing air quality reports provided by the U.S. Embassy and saw the reading for 9:00 a.m.:
No matter how blue the sky may appear, I wouldn't consider an "unhealthy" air quality index (AQI) of 154 to be semi-decent.

I then thought about my days in Shanghai where it is not uncommon to hear people say something like "yeah, the air isn't great here, but it's much better than Beijing!" So I was curious to see what the U.S. Consultate in Shanghai reported at the same time:
155, I'd call that a draw.

For another comparison, I checked more recent readings while writing this post:

Shanghai's 161 is in a different category than Beijing's 112. We had a winner.

And now I wondered how a U.S. city would compare. I found that at the same time (8:00 p.m. Saturday night) current readings in Central Los Angeles, one of the most polluted cities in the US, indicated an AQI of 59 and the forecast for Sunday was 45--considered "good" for a 24 hour period. For the U.S. it's nothing to be especially proud of, but a 45 would seem great to me right now.

Of course, these are a very small number of data points. They're representative in some regards, but I wouldn't make any strong conclusions based on them alone. My main points for now are basic. I found it easy to think the air was OK when in fact it wasn't. And even if Shanghai has not seen some of the extreme pollution that can occur in Beijing, there's still good reason for people in Shanghai to also be concerned.

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