The Air Quality Index (AQI) is a globally used index of pollution levels. It vividly explains dry numerical data. Therefore, for many people, it is the simplest and most logical way to communicate the level of air pollution. It is on a scale from 0 to 500. Naturally, the higher the indication, the more polluted the air around us.
What is taken into account in determining the AQI?
To assess air quality, the AQI index uses, among other things, levels of PM2.5 and PM10 particulate matter, as well as certain gaseous pollutants – sulfur dioxide (SO2), ozone (O3), nitrogen oxide (NO), carbon monoxide (CO) and benzene, which are most often the result of fuel combustion. The situation gets more complicated when one realizes that there are actually several AQI scales, depending on the country or region of the world. China may interpret PM2.5 and PM10 readings differently, the US differently, and Mexico, India or Canada still differently.
How to read the index?
AQI values at or below 50 are generally considered very good. When AQI values exceed 100, air quality is unsatisfactory and can negatively affect sensitive people. Scores over 150 are already unhealthy for the general public, while those with values over 300 are already extremely unhealthy.