What is AQI?
The Air Quality Index (AQI) is a standardised indicator used worldwide to communicate how polluted the air currently is. Think of it as a thermometer for air quality — the higher the number, the greater the health concern.
How is AQI Calculated?
AQI monitors measure concentrations of major pollutants: ground-level ozone (O₃), particle pollution (PM2.5 and PM10), carbon monoxide (CO), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂). The highest sub-index among these pollutants becomes the reported AQI value.
AQI Scale Breakdown
- 0–50 (Good) — Air quality is satisfactory. Enjoy outdoor activities.
- 51–100 (Moderate) — Acceptable, but sensitive individuals should limit prolonged outdoor exertion.
- 101–150 (Unhealthy for Sensitive Groups) — People with respiratory or heart conditions should reduce outdoor activity.
- 151–200 (Unhealthy) — Everyone may begin to experience health effects.
- 201–300 (Very Unhealthy) — Health alert: everyone should reduce outdoor exposure.
- 301+ (Hazardous) — Emergency conditions. Avoid all outdoor activities.
Practical Tips
Check the AQI before planning outdoor exercise. Use our dashboard for real-time readings in your area, and set alerts so you never miss a spike.
