sentences:  Readings by the Chiang Mai Air Quality Health Index (CMAQHI) showed air quality index (AQI) scores in Samoeng's tambon Yang Moen had exceeded 500, the highest level the AQI can record.The AQI measures a spectrum of air pollutants including PM2.5, PM10, and carbon dioxide.PM2.5 is particulate matter (PM) with a diameter of less than 2.5 micrometres, or about 3% the diameter of a human hair.