El Nino Watch
The worse of the last 24-hour average of PM2.5 and the worst 24-hour average forecast for the next 72 hours, scored with the Thai PCD bands.
Koh Samui watch
Data: modelled PM2.5 from the Copernicus Atmosphere Monitoring Service (CAMS), through Open-Meteo. It is a model, not a monitoring station: compare with Air4Thai (the Thai Pollution Control Department network) when in doubt.
Samui is usually clean, but El Nino years bring haze from fires in Indonesia and Malaysia (2015, 2019).
| PM2.5, 24 h average | Thai PCD band | Factor level |
|---|---|---|
| 37.5 µg/m³ or less | very good to moderate | 0 Normal |
| 37.6 to 75 | starting to affect health | 1 Watch |
| 75.1 to 125 | affects health | 2 Prepare |
| above 125 | affects health (above 125.4 = US EPA "very unhealthy") | 3 Act |
Cap: 3. Not a critical factor. Stale after 12 h without an update.