By THE NATION
The Air Quality and Noise Management Division of Bangkok said that the level of particulate matter less than 2.5 micrometres in diameter (PM2.5) was around 9 to 27 micrograms per cubic metre (µg/m3).
The Air Visual application reported on Sunday that Bangkok’s air pollution level, according to the US Air Quality Index (AQI) standard, stood at 49, with the level of PM2.5 at 12 per cubic metre (µg/m3).
As of 9.30am, Bangkok ranked 67th on the list of cities with the worst air quality in the world, while Chiang Mai was at 42nd with PM2.5 at 24 micrograms per cubic metre.
AQI is a standard that indicates the quality of air and level of pollution. Level 0-50 is good air quality, 51-100 is moderate quality, 101-105 starts affecting sensitive groups, 151-200 is slightly harmful to health, 201-300 is highly harmful and 301-500 is extremely dangerous.