On the IQAir platform, including the IQAir AirVisual Pro indoor air quality monitor, users can choose to display either the U.S. AQI or China AQI. The thresholds for pollutant concentrations differ between the two systems, which is why the same air quality measurement can result in different AQI values depending on which index is selected.
The tables below will show you how pollutant concentration breakpoints compare between the U.S. and China AQI systems. These breakpoints are set by their respective environmental agencies, reflecting their national guidelines on air quality and health risk communication.
The U.S. AQI is based on the Environmental Protection Agency (EPA) standards, which classify air quality into six categories, ranging from "Good" to "Hazardous." The China AQI, defined by the Ministry of Environmental Protection of China, has similar categories but uses slightly different pollutant thresholds.
On the IQAir platform, you can switch between U.S. AQI⁺ and China AQI⁺ to see how air quality levels compare between these two standards. U.S. AQI⁺ is a more real-time version of the U.S. AQI, calculated using hourly averages to provide more timely air quality information. For more detailed information on how AQI and AQI⁺ work, please refer to our article What is the air quality index (AQI)?
