Table 4 WHO 2021 pollutants air quality...

Table 4

WHO 2021 pollutants air quality guideline (AQG)

Pollutant	Averaging time	Interim target				AQG level
		1	2	3	4
PM_2.5 µg/m³	Annual	35	25	15	10	5
PM_2.5 µg/m³	24 – hour*	75	50	37.5	25	15
PM₁₀ µg/m³	Annual	70	50	30	20	15
PM₁₀ µg/m³	24 – hour*	150	100	75	50	45
O₃ µg/m³	Peak Season	100	70	–	–	60
O₃ µg/m³	8 – hour^a	160	120	–	–	100
NO₂ µg/m³	Annual	40	30	20	–	10
NO₂ µg/m³	24 – hour^a	120	50	–	–	25
SO₂ µg/m³	24 – hour^a	125	50	–	–	40
CO mg/m³	24 – hour^a	7	–	–	–	4

Pollutant	Averaging time	Interim target				AQG level
		1	2	3	4
PM_2.5 µg/m³	Annual	35	25	15	10	5
PM_2.5 µg/m³	24 – hour*	75	50	37.5	25	15
PM₁₀ µg/m³	Annual	70	50	30	20	15
PM₁₀ µg/m³	24 – hour*	150	100	75	50	45
O₃ µg/m³	Peak Season	100	70	–	–	60
O₃ µg/m³	8 – hour^a	160	120	–	–	100
NO₂ µg/m³	Annual	40	30	20	–	10
NO₂ µg/m³	24 – hour^a	120	50	–	–	25
SO₂ µg/m³	24 – hour^a	125	50	–	–	40
CO mg/m³	24 – hour^a	7	–	–	–	4

Note(s): ^a99^th percentile (i.e. 3–4 exceedance days per year)

^bAverage of daily maximum 8-h mean O₃ concentration in the six consecutive in six months with the highest six-month running-average O₃ concentration

Source(s): WHO (2021)

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