The Air Quality Index, or AQI, is a standardized system used to measure and communicate the quality of air in a specific area. It provides information about how polluted the air currently is or how polluted it is forecast to become. The AQI is calculated based on the concentrations of various pollutants, including PM2.5, PM10, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The AQI is typically represented on a scale from 0 to 500, with lower values indicating better air quality and higher values indicating worse air quality. Different ranges correspond to different health effects, helping people understand when they should take precautions, especially those with respiratory issues or other health concerns.