I have lived in North-Chiang Mai for more than 10 years, until I came to live on the coast because of the pollution levels and to save my family from that danger. My diagnosis; Pulmonary Emphysema. (I don't drink and I don't smoke). It is not a healthy place to live and even less so at this time of year. If you are going to visit the place for a few days, try to use masks outdoors.. Good luck!.
CM Today.