🌍Real-time Air Quality Index
Understanding the air you breathe, updated in real-time
What is AQI?
The Air Quality Index (AQI) is a standardized indicator that tells you how clean or polluted your air is, and what associated health effects might be a concern for you.
The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. It considers several major air pollutants regulated by the EPA and WHO:
- Particulate Matter (PM2.5 and PM10)
- Ground-level Ozone (O₃)
- Nitrogen Dioxide (NO₂)
- Sulfur Dioxide (SO₂)
- Carbon Monoxide (CO)
Think of the AQI as a yardstick that runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern.
How Often We Update
Readings refresh every hour, and the figure you see is built from pollutant concentrations rather than the other way round.
Concentrations first
PM2.5, PM10, NO₂, O₃, SO₂ and CO come from Open-Meteo in µg/m³. The index is calculated from them, so the number and the measurement behind it always agree.
A 24-hour average
The AQI is defined on a 24-hour average, not the current instant. A single hour of bad air does not spike it, and a clean hour does not hide a bad day.
Your country's scale
In India, China and Thailand the headline number is recomputed under CPCB, HJ 633 or PCD, so it matches what a local government app would show. Everywhere else uses the US scale below.
Told before it turns
The app looks two hours ahead and alerts you when air quality is forecast to cross your country's threshold, so you hear about it before you step out.
The scale below is the US AQI. See how each country's standard differs and why the same air gets different labels.
Understanding the Numbers
The AQI is divided into six categories, each corresponding to a different level of health concern:
Air quality is satisfactory and poses little or no risk.
Fine for outdoor activity, with no health concerns for any group.
Acceptable for most people, though sensitive individuals may notice minor effects.
Generally fine outdoors. Unusually sensitive people may want to ease off prolonged exertion.
Sensitive groups may experience health effects. The general public is less likely to be affected.
Children, older people and those with respiratory conditions should limit prolonged exertion outdoors.
Everyone may begin to experience health effects, and sensitive groups more serious ones.
Reduce prolonged or heavy exertion outdoors. Sensitive groups should avoid it.
Health alert: the risk of health effects is raised for everyone.
Avoid prolonged or heavy exertion. Move activity indoors or reschedule it.
Health warning of emergency conditions. Everyone is more likely to be affected.
Avoid all outdoor exertion. Stay indoors and keep activity levels low.
Ready to Track Your Air Quality?
Get real-time AQI updates, a full pollutant breakdown, and pollen forecasts for your exact location.
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