El Nino Watch
The European Copernicus model that forecasts air pollution worldwide (about 45 km globally). The app's PM2.5 for Samui comes from it, not from a local station.
Data and trust
CAMS (Copernicus Atmosphere Monitoring Service) simulates smoke, dust and pollution around the world and forecasts it several days ahead. Globally its grid is about 0.4° (about 45 km).
Good at: seeing a regional haze episode coming. Weak at: local sources (a nearby fire, traffic). Compare with the Thai Pollution Control Department stations on Air4Thai.