The US embassy in Beijing runs their own particulate pollution monitor, as the Chinese government's are somewhat suspect. A few years ago, the level became so high that it ran off the end of the scale. The programmer had put in a descriptor of "Crazy Bad" for that level as a joke, and that ended up being posted to the official Twitter feed.

http://blogs.wsj.com/chinarealtime/2010/11/25/shanghai%E2%80...