PSI (Pollutant Standards Index)
Pollutant Standards Index
Just Tell Me
PSI is Singapore’s air-quality index, turning measurements of six pollutants into a number that describes pollution levels.
Also called: Pollutant Standards Index, 24-hour PSI, 24-hr PSI
Explain Like I’m Five
Singapore’s monitoring stations measure several kinds of air pollution. PSI turns those measurements into a shared scale, so people can understand an air-quality report without comparing six separate pollutants. Higher readings mean worse air quality on that scale.
How It Works
Each pollutant gets its own index score; the highest determines the reported PSI. The 24-hour PSI reflects a rolling day of measurements, even though readings are updated hourly.
Where You’ll Run Into It
On the myENV app, NEA’s haze website and Singapore news reports about conditions around your neighbourhood. Readings are reported for five regions.
Compare a monsoon forecast when you need weather context; rain and seasonal winds are different from the pollution index.
Example
“That screenshot shows yesterday’s PSI. Let’s check the updated report.”
A resident checks the time and region instead of assuming an old number describes conditions near home now.
The Part People Get Wrong
An hourly update does not make the 24-hour PSI a one-hour measurement. NEA publishes a separate one-hour PM2.5 reading for more immediate conditions; its PSI forecast and accompanying advisory help with planning ahead during haze.
Sources
Related
- moneyTransboundary Haze Pollution Act (THPA)Updated
The Transboundary Haze Pollution Act is Singapore’s law addressing conduct that causes or contributes to haze here, including conduct outside Singapore.
- housingMonsoon in SingaporeUpdated
A monsoon is a seasonal wind pattern that helps shape Singapore’s weather, including when prolonged rain or brief thunderstorms are more likely.
- moneyNEA (National Environment Agency)Updated
NEA is Singapore’s National Environment Agency, responsible for environmental protection, public cleanliness and hygiene, waste management, weather services and hawker-centre development.
- housingPM2.5Updated
PM2.5 means fine airborne particles measuring 2.5 micrometres or less; Singapore reports their concentration to help people understand air quality, especially during haze.