Living standards in Hangzhou are better than Hohot or for that matter the Chinese hinterland as a whole, although in general air quality in all Chinese cities is poor. I hear that a proposal was put forward at the recent 'two meetings' to extend the public heating system into Southern China which would be a welcome relief from the cold and damp San Migs described. It really does get into your bones!

If environment/pollution is a major factor in her choosing a destination then 2nd tier cities in wealthy provinces often provide cleaner living (although it is always relative to what you're used to i guess!)

She can get immunised against certain strains of pneumonia as well as influenza which might help.