Air Quality in China

For air quality data in China, note the following:

• AQI calculations follow the Technical specifications on ambient air quality index (HJ 633—2026).
• QAQI is not currently supported.
• Detailed pollutant data is not available in air quality forecasts.
• When a pollutant sub-index is below 50, the primary pollutant for AQI (CN) and AQI-1H (CN) is null.
• Air quality indices are calculated from numerical models and monitoring station data. They have not been revised or confirmed through a complete review process and must not be used to assess compliance or for any official evaluation. They are provided for reference only.