They don't, but a medical system doesn't make the air cleaner nor stop diseases from occuring. It only means better treatment is available. But I'm sure my lungs are not in great shape from 15 years of smoking and living in NYC....still, I bet I'm better off than someone living in Delhi or Beijing regardless of medical care (And I'm sure I'd probably get better medical treatment in Bejing or Delhi than NYC considering socioeconomics).