Haze Day Why do apps show different numbers: US AQI, Singapore PSI and Malaysia API?
They are different indices with different formulas and breakpoints, and some apps use low-cost sensors or models. A US AQI of 250 can sit alongside a Malaysian API of about 175, so compare like with like and trust the local official index.
Singapore now · loading the official reading…
What we show
For Singapore we show NEA's official 1-hour PM2.5 and 24-hour PSI. For other places we show a clearly labelled model estimate and link to the official source (for Malaysia, DOE's APIMS).
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Sources
- NEA 24-hour PSI (Singapore) — National Environment Agency (NEA), Singapore · official site · API / docs
- Malaysia DOE APIMS / MyJAS — Department of Environment Malaysia (DOE) · official site
- CAMS PM2.5 model via Open-Meteo — Copernicus Atmosphere Monitoring Service (ECMWF); served by Open-Meteo · official site · API / docs