AQI Calculator
Enter pollutant concentrations to estimate an Air Quality Index using a selected reference method. The result is a calculation from your inputs, not a live monitoring reading.
Important: AQI methods use specified averaging periods, units and pollutant-specific breakpoints. Enter values that match the selected method. This tool is for information and comparison, not regulatory reporting.
How the AQI is calculated
Most AQI systems calculate a separate sub-index for each pollutant. The highest applicable sub-index becomes the reported AQI, and the pollutant producing that value is the dominant pollutant. The U.S. EPA describes a linear interpolation method between concentration breakpoints; India's CPCB framework likewise uses pollutant sub-indices and the highest sub-index.
Use the right scale
AQI numbers are not globally interchangeable. A value such as 100 can represent different concentration ranges under different national or regional methods. For that reason, AirQualityIndex.org identifies the reference scale instead of presenting one number as a universal standard.
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