On Scale of 0 to 500, Beijing’s Air Quality Tops ‘Crazy Bad’ at 755 
I lived there in '08 and '09. You cannot believe it until you have seen it. The difference during the Olympics was stark. For example, my apartment in Shijingshan had a view of a mountain (~5 mi) and a comm tower (~1 mi). I lived in that apartment for a month before I ever saw either of them. The 'Jing rarely gets full sunlight, rather there is this kind of yellowish lambertian light source in the white-ish gray sky. People who espouse environmental deregulation should go check it out.