Scary Air Pollution in Numbers

I just heard about BeijingAir, which twitters hourly readings of air pollution as measured from the US Embassy's roof. I'm not sure why I clicked on the link. The scary "Unhealthy" to "Very Unhealthy" readings for the past few days are no surprise.

Knowledge is power, so they say. Power to decide when to bring your dust mask when walking down the street to buy orange juice, power to barricade yourself indoors when you can actually see the air. . .