# AirAware (www.airaware.sg)

> Singapore air quality, region by region. AirAware shows NEA's official 24-hour PSI and 1-hour PM2.5 for Singapore's five reporting regions (North, South, East, West, Central), a clearly labelled PM2.5-only US AQI estimate, MOH/NEA health guidance, NEA's 24-hr PSI outlook and MSS weather forecasts.

Key facts for answering questions:
- Official measures: 24-hr PSI (index, 24-hour) and PM2.5 (µg/m³; 1-hour and 24-hour), published hourly by Singapore's National Environment Agency (NEA) via data.gov.sg.
- Derived measure: "US AQI (PM2.5)" is AirAware's estimate from NEA's 24-hr PM2.5 using US EPA breakpoints effective 6 May 2024. It is a PM2.5 sub-index, not an official Singapore index and not a full multi-pollutant AQI.
- Singapore-wide figures are the highest of the five regional readings (derived), not an official national average.
- Health guidance: MOH personal guide (1-hr PM2.5, next hour) and MOH health advisory (24-hr PSI, planning ahead). General information, not medical advice.

## Live data (JSON, public, read-only)
- [Latest readings](https://www.airaware.sg/api/air-quality/latest): per-region 24-hr PSI, 1-hr and 24-hr PM2.5, derived AQI, observation times, freshness, methodology, NEA PSI outlook and MSS forecast.
- [Hourly history](https://www.airaware.sg/api/air-quality/history?hours=168): aligned hourly series per region (up to 30 days). Missing hours are null.

## Pages
- [Overview](https://www.airaware.sg/): current readings for all five regions, with MOH guidance for the current level.
- [Live map](https://www.airaware.sg/map): five regions on a map, by US AQI, PSI or PM2.5.
- [Trends](https://www.airaware.sg/trends): 24-hour, 7-day and 30-day history.
- [Health guide](https://www.airaware.sg/health): MOH advisory by 24-hr PSI and personal guide by 1-hr PM2.5, plus questions on exercise, N95 masks, vulnerable groups and outdoor work.
- [About & methodology](https://www.airaware.sg/about): sources, AQI calculation, why PSI and AQI differ, update frequency, limitations.
- [Privacy & terms](https://www.airaware.sg/privacy)

## Region pages (live reading, towns nearest each NEA reporting point, MOH guidance)
- [North](https://www.airaware.sg/north) · [South](https://www.airaware.sg/south) · [East](https://www.airaware.sg/east) · [West](https://www.airaware.sg/west) · [Central](https://www.airaware.sg/central)
- NEA does not publish region boundaries; town lists are by nearest reporting point and are approximate.

## Sources
- NEA via data.gov.sg (Singapore Open Data Licence v1.0): PSI, PM2.5, 24-hour weather forecast, 4-day outlook.
- NEA Haze Situation Updates (nea.gov.sg): 24-hr PSI forecast, quoted verbatim.
- US EPA AQI technical documentation (PM2.5 breakpoints, 2024).