The free Air Quality Index by City
Check the air quality index (US AQI) for any city right now: PM2.5, PM10, ozone, NO₂, SO₂ and CO compared with WHO guidelines.
- Free to use
- No signup
- Nothing to install
- Works in any modern browser
Delhi · AQI 168 — Unhealthy · PM2.5 at 480% of the WHO guideline → limit outdoor exertion; sensitive groups stay in.Open the Air Quality Index by City
Illustration. Open the tool for the real thing.
See it in action
Sample input: Search a city, e.g. Delhi, Beijing, Los Angeles = London. Pressed Search.
What is the Air Quality Index by City?
Search any city, or use your location, to see its air quality right now. You get the US Air Quality Index with a colour and category from Good to Hazardous, a plain-language health message, and the readings for the main pollutants — PM2.5, PM10, nitrogen dioxide, ozone, sulphur dioxide and carbon monoxide — each compared with the World Health Organization's air-quality guideline values.
A 48-hour chart shows how the AQI is expected to change so you can pick the best time to run, cycle or open the windows. Data comes from the Open-Meteo air-quality service, which uses the CAMS atmospheric model; it is a model estimate rather than a reading from a nearby sensor, so treat it as a reliable guide and follow local authority alerts during wildfires or smog episodes.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Colour-coded category and what to do about it.
See which one is driving the pollution.
Plan outdoor activity around cleaner hours.
Worldwide coverage.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
How it compares
A plain look at this tool next to the usual alternative.
| This utility | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
Questions people ask
What is a good AQI?
0–50 is Good, 51–100 Moderate, 101–150 Unhealthy for sensitive groups, 151–200 Unhealthy, 201–300 Very unhealthy, above 300 Hazardous.
What is PM2.5?
Particles smaller than 2.5 micrometres that can enter the lungs and bloodstream. WHO recommends a 24-hour average below 15 µg/m³.
Where does the data come from?
Open-Meteo's air-quality API, based on the Copernicus CAMS model.
Is it a real sensor reading?
No, it is a model estimate. For hyper-local readings use a nearby monitoring station or an air sensor.
Which AQI scale is used?
The US AQI is shown large, with the European AQI as a small extra.
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