Most years, air quality in Samoeng declines in March–April due to field burning and forest fires. In April 2019, Samoeng's air quality declined to levels heretofore unseen. To blame were forest fires in the hills surrounding the valley. 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. It can lodge in the lungs and enter blood vessels, leading to respiratory and cardiovascular disease. ==History==