Is someone's request about living in Kunming the best place for a pissing contest?
For the actual relevant questions posted:
1) HK vs Kunming Pollution. There is more to pollution than air pollution. Kunming's air pollution rates can be just as high as HKs, even though we get more blue sky (an effect of the altitude, not pollution). However, Kunming has higher levels of pollution in water and animal protein. These may not make someone sick immediately, but they can have health effects in the long-run. Similarly smoking is more prevalent, so if someone or a member of their family is particularly sensitive to it (example, someone having recently undergone cancer treatment or who is prone to recurrence) then Kunming may not be the best place. This is also a general problem in China, as CERTAIN health problems connected to pollution are much higher here than elsewhere, but only manifest in late-life.
2) Medical Care: There is good medical care in Kunming that will cover a majority of problems someone would face. However, if a person has very specific problems, Kunming would be a bad idea. Orthopedic surgery is really lacking here, so people with chronic joint pain/back pain or who has sustained injuries that would require precise surgery would do well to think twice before relocating. Similarly, if someone had a child/spouse/etc who required ongoing mental health care, then probably stay in the larger cities or outside China. The infrastructure is simply not here.
3) Location based problems: Different people have different sensitivities to their environment, so yes where they live can affect their health. For example, actually yes if someone is prone to current headaches or has chemical sensitivities, then SLC, UT may be a better option. Lower altitude, fewer plants, and a long winter that kills everything off in the air would have many benefits for someone like that. My stepmother had severe allergies living in SoCal, to the point that she (as a restaurant critic) lost her sense of smell and taste. She relocated to Boston where the plants are different and the winter freezes everything—surprise, she can smell and taste again.
Sidepoint, SLC, UT is awesome. Amazing food and environment there.