I’ve told this to people again and again: In Beijing, the pollution can be horrible (though not as bad as Guangzhou), but you’ll also get some lovely days of perfect wheather as well. These photos prove it!
It may only be about one day per week, but it does happen!
Edit 4 July 2012: Unfortunately, it seems that the pollution and air quality in Beijing has gotten steadily worse and is at a new low point. There are still a few blus sky days, but not as many as there once were. Here’s to hoping that some of the measures the Chinese government is taking actually helps them.