Updated: 08/16/2021 by Computer Hope

Short for air quality index, AQI is a measurement of the breathable air quality with a value between 0 (zero) and 500. The higher the AQI value, the greater the level of air pollution and concern for health. Microsoft Windows 10 users may notice the AQI listed next to the weather in the Windows notification area, as shown below. In this case, the AQI is 126.

Windows 10 notification area with the weather and AQI


The weather and AQI are related to the location data saved on your Microsoft account. They are not based on the location of the computer or its temperature.

AQI values

Below is an overview of the AQI index values and their description from AirNow.

Value Description
0 to 50 Air quality is good, with little or no risk to health.
51 to 100 Air quality is acceptable, but may be a risk for some particularly sensitive people.
100 to 150 Air quality is unhealthy, and sensitive people may experience health effects.
151 to 200 Air quality is unhealthy, and generally healthy people may experience health effects. Sensitive people may experience serious health effects.
201 to 300 Air quality is very unhealthy, and health risk is increased for everyone.
301 and higher Air quality is hazardous and affects everyone.

Windows notification area