You'll spend your first 4 or 5 moths in Shijiazhuang and the pollution here is unreal. Some of the worst in China and China has the worst in the world. You'll develop the habit of hacking and spitting here on a regular basis (this is normal and you'll see everyone doing it, even old women--on the train, busses, even occasionally in hotel lobbies).
Well, the main reason for the spitting, hacking etc. is not the pollution, it is simply because they are Chinese
