Detailed legend

The AQI is based on the measured values of up to six key pollutants (O₃, NO₂, SO₂, PM₁₀, PM_2.5) to determine the degree of air pollution at the site of each device. The index corresponds to the poorest level of any of the six pollutants based on the following ranges.

Pollutant	Level index (based on pollutant concentrations in µg/m₃)
Pollutant	Good	Fair	Moderate	Poor	Very poor	Extremely poor
	(0-25)	(26-50)	(51-75)	(76-100)	(101-125)	(126-200)
PM_2.5 (24h)	0-10	10-20	20-25	25-50	50-75	75-800
PM₁₀ (24h)	0-20	20-40	40-50	50-100	100-150	150-1200
NO₂	0-40	40-90	90-120	120-230	230-340	340-1000
O₃ (8h)	0-50	50-100	100-130	130-240	240-380	380-800
SO₂	0-100	100-200	200-350	350-500	500-750	750-1250

Reference: National Air Quality Index Regulation