just to bounce off your post since you mentioned smokers (i.e, ACE-2s) - is this limited only to cigarette tobacco or could that relate to combustible materials per se? Or even those with high exposure to combustible materials such as first responders? Firemen/emt/leo ?
In China much of the adult male population smokes cigarettes, but just breathing the air in most Chinese cities damages a persons lungs.
As for first responders here, they are normally physically healthy (yes with exceptions), but some occupational exposure I suppose?
Every time I’ve been to China I can feel the poor air quality- I can’t imagine spending my life there.