A USDOT University Transportation Center

The Air Quality Index (AQI)

The Air Quality Index (AQI) is a tool for assessing ambient air quality. The tool informs the user of the concentration of vehicle emissions in the atmosphere and how they affect health. From 0 to 500, the AQI scale ranges from excellent to severe. To calculate the air quality index (AQI), eight primary pollutants must be considered: lead, particulate matter (PM10 and PM2.5), carbon monoxide, ozone, nitrogen dioxide, sulphur dioxide, and lead (Pb). Data for a minimum of three pollutants, one of which should be either PM10 or PM2.5, must be available to compute AQI.

This tool will help achieve the goal of the following objectives

  • Less Contamination
  • Less Emissions
  • Less Traffic Noise
  • Connectivity and Inclusion
  • Healthy Destinations
  • Less Traffic Violence
  • Active Transportation
  • Green Space

Estimation Technique

The tool uses a sensor to measure the level of pollutants in the air. The yardsticks range from 0 to 500 and vice versa; the greater the AQI number, the higher the amount of air pollutants.
A good result falls in the 0–50 range and has little to no negative effects on health. However, if the outcome is more than 200, there are significant levels of pollutants in the air that might negatively impact people’s health.