Need a hand with a reading?

AirSG keeps the last good reading and shows an amber OFFLINE chip when a refresh fails. Check the connection, then pull down to refresh or tap the refresh button. If only one provider is down, the app may still show NEA data, a WAQI station or an Open-Meteo model estimate — the badge tells you which source is on screen.

Open iOS Settings → Privacy & Security → Location Services → AirSG and allow While Using the App. For alerts that follow you when you travel, allow Always; without it, the app still updates while it is open. If you would rather not share location, search for a city or place instead — AirSG works with a searched place.

Check three things: the alert is switched on in AirSG Settings; iOS Settings → Notifications → AirSG allows notifications; and the threshold has actually been crossed (haze alerts wait for a second check at least 60 seconds later, and re-arm only after the reading falls 10 points below the threshold or at 08:00 local). Background checks are requested at your auto-refresh interval, but iOS decides if and when they run — they pause in Low Power Mode and stop if you swipe the app away. Rain-nearby alerts have a 60-minute cooldown.

Because they measure different things. NEA publishes an official 24-hour PSI for each of its five Singapore regions. A WAQI station reports a US AQI for its own location. Open-Meteo is a grid model, not a station. AirSG shows them separately and never blends them into one figure — the source badge and scale label tell you which is which.

WAQI has no reporting station close enough to that place, so AirSG falls back to the Open-Meteo model. The badge says MODEL ESTIMATE, and the app never labels a model value as a station reading. Rankings are model data too, and say so.

The 70 km radar covers Singapore and the surrounding area only. It appears when the map viewport intersects the radar footprint. Frames update every few minutes; if NEA has not published a new frame, the latest one stays on the map. Playback runs from 24 hours ago to now.

Yes. Singapore uses official NEA data; anywhere else the app uses the nearest WAQI station and falls back to the Open-Meteo model where stations are sparse. The source and scale are labelled on every reading.

There is no account and no server-side profile. Your settings, cached readings and alert state live on the iPhone; deleting the app removes them. You can also revoke location, notifications or background refresh in iOS Settings at any time.

There is nothing to refund: AirSG is free, with no in-app purchases or subscriptions.