South Singapore haze now: PSI and PM2.5 today

NEA reports haze for five regions: North, South, East, West and Central. NEA does not publish station locations or region boundaries in its data feed, only one reference point per region, so the site shows the region whose point is nearest to you. Close to a boundary that can differ from what you expect. Tap any region to switch. Your location is only used on your device and is never sent anywhere.

The big number is 1-hour PM2.5: the fine particles in the air over the last hour, in micrograms per cubic metre. It moves fastest, so it is the best guide to right now. NEA calls it Normal up to 55, Elevated from 56 to 150, High from 151 to 250 and Very High above 250.

The 24-hour PSI is Singapore's official index. It averages the last 24 hours, so it rises and falls more slowly. Up to 50 is Good, 51 to 100 Moderate, 101 to 200 Unhealthy, 201 to 300 Very Unhealthy and above 300 Hazardous.

The wording follows NEA's guide for 1-hour PM2.5 and the Ministry of Health's advisory for 24-hour PSI. When the two readings point to different advice, the site shows the stricter one and says which reading it came from. "With kids or elderly" switches to the advice for vulnerable groups.

Sites such as aqicn.org convert PM2.5 into the US Air Quality Index, which is a stricter scale than NEA's bands. The same air can be Elevated on NEA's scale and Unhealthy on the US one. The US scale row shows that conversion (US EPA table, 2024) so you can compare. It is designed for 24-hour averages, so on a single hour it is approximate.

Readings come from NEA through data.gov.sg and are published about once an hour. The page checks for a new reading every five minutes while it is open, and warns you if the latest one is more than 90 minutes old. This is not an official NEA site.