Table 4.

Individual air quality index (IAQI) and corresponding pollutant concentration limit⁵².

IAQI	Pollutant concentration limit (μg m−3)
	SO2		NO2		PM10	CO (mg m−3)		O3		PM2.5
	24-h average	1-h averagea	24-h average	1-h averagea	24-h average	24-h average	1-h averagea	1-h average	8-h average	24-h average
0	0	0	0	0	0	0	0	0	0	0
50	50	150	40	100	50	2	5	160	100	35
100	150	500	80	200	150	4	10	200	160	75
150	475	650	180	700	250	14	35	300	215	115
200	800	800	280	1200	350	24	60	400	265	150
300	1600	b	565	2340	420	36	90	800	800	250
400	2100	b	750	3090	500	48	120	1000	c	350
500	2620	b	940	3840	600	60	150	1200	c	500

^a1-h average concentration limits of SO₂, NO₂, and CO are only used in real-time reporting, and the 24-h average concentration limits of SO₂, NO₂, and CO are used in daily reporting.

^bWhen 1-h average concentration limit of SO₂ is higher than 800 μg m⁻³, the individual air quality index of SO₂ is not reported and the reported individual air quality index of SO₂ is calculated by 24-h average concentration limits.

^cWhen 8-h average concentration limit of O₃ is higher than 800 μg m⁻³, the individual air quality index of 8-h average concentration of SO₂ is not reported and the reported individual air quality index of SO₂ is calculated by 1-h average concentration limit.