We have lived in central Thailand for many years but it is time to move to where our kids can get a good education. Chang Mai seems to be the answer going by information in this thread.

My worry is the air quality during the burning season. Our youngest son is sensitive.

How bad is the air quality during burning season? Is there an area we can live that isn't so bad yet near enough to international schools?

The worst however this year it wasn't a problem because of all the rain.

Last year I drove as far as Khon Kaen before the smoke thinned out. I sat in the airport departure lounge and could barely make out Doi Suthep which is 3-5km away. Unfortunately it isn't just Thailand, its from burning in Burma and Laos as well. I have extra filter material on the aircons and seperate air filters which helps to make life easier inside the house. It can get unpleasant. As Venturalaw says, this year has been very good because of the early rains.

Maybe I'm a little biased, but IMO Chiang mai is about the best place I've ever been, having traveled now to 58 countries. The burning season, which can last from mid February till April is not pleasant. Most days that unpleasantness manifests itself as less visibility to greater distances. Some days, especially those in March, can manifest itself as less visibility AND poorer air quality. This year we had neither. Next year we may have both. The trend is towards improved air quality but any given year may be worse than another.

Interesting unusual spread between Chiang Mai (14) and Uparaj (65.9) PM<10 readings for 10 May. Might we speculate that this the "Diesel Exhaust Difference?"