Here are some PM2.5 readings, taken with a Mi  PM2.5 meter, which fits nicely into a pocket.    I believe the units are microgrammes per cubic meter, but have temporarily misplaced the instructions.  

The first 9 results are in Bangkok and the bottom 5 are in Europe.

In Bangkok, indoor readings tend to be lower than outdoors.

Considering only PM2.5 exposure, I'd be better off sleeping directly behind my old diesel car with the engine running, than in the hotel in Bangkok.    The hotel aircon claims to have a filter, since the display had a warning to change the filter.   I doubt that would be necessary, as the block I was in only opened in January 2021.   

My exposure outdoors should be reduced markedly this year, as I've been wearing an N95 face mask for covid.

If I had an apartment in Thailand, I'd be buying one of those air filters.     As a tourist, they are way to big to carry around.  I've noted you can buy some PM2.5 air filter material to go in aircon units.

 

Very interesting and sobering data there Z909. During my occasional visits to Bkk I used to go running in Lumpini Park in the early evening and found breathing the air not good and so kept the runs short. I suppose that air quality in Pattaya would be variable but mostly better, particularly on the beach and in the Complex. I recall stopping at a cafe on a busy road there and having to sit virtually next to the road in amongst the fumes from innumerable motor bikes and diesel baht buses. I shifted my seat when one further back  became vacant. A waitress said “you no like sit there” I replied about the fumes and she said it was bad for those who work there.