Air & haze
Singapore haze, PSI and PM2.5 right now
NEA's hourly readings for all five regions, on NEA's scale and the US EPA scale.
By region
Large figure: latest 1-hour PM2.5 (µg/m³). Small: 24-hour PSI and the US EPA AQI equivalent. NEA publishes both hourly, a few minutes past the hour.
All pollutants
| Pollutant | NEA reading | NEA index | US AQI |
|---|
NEA index is the PSI sub-index; the US column converts the same reading with the EPA's current breakpoints (PM2.5 table revised May 2024). Where averaging periods don't match, the US column is left blank rather than estimated.
Last 48 hours
| Hour | N | W | C | E | S |
|---|
Archive since 2014
| Hour | N | W | C | E | S |
|---|
NEA's historical datasets on data.gov.sg, hourly by region from April 2014, refreshed about monthly; the most recent weeks are not yet in it. The archive follows the NEA / US AQI scale chosen above.
Questions
What is the difference between PSI and PM2.5?
The 24-hour PSI is NEA's headline index, a rolling average of six pollutants over the past day; it moves slowly and is what health advisories are written against. The 1-hour PM2.5 is the concentration of fine particles right now and is the first number to move when haze arrives.
Why does aqicn.org show a higher number than NEA?
Both use NEA's readings. aqicn converts the 1-hour PM2.5 to the US EPA Air Quality Index, whose bands are stricter than NEA's: a reading NEA calls 'elevated' (56–150 µg/m³) is 'unhealthy' (151–200) on the US scale. SGWeather shows both.
When is haze season in Singapore?
Transboundary haze from land and forest fires in the region is most likely from August to October during the Southwest Monsoon, particularly in drier years; it can also occur in March under north-easterly winds.