 As of 28 August 2008, SEPA monitored daily pollution level in 86 of its major cities.The AQI level was based on the level of 5 atmospheric pollutants, namely sulfur dioxide (SO2), nitrogen dioxide (NO2), suspended particulates (PM10), carbon monoxide (CO), and ozone (O3) measured at the monitoring stations throughout each city.AQI Mechanics
An individual score is assigned to the level of each pollutant and the final AQI is the highest of those 5 scores.