Graphic Yearbook

Tab. I.3 WHO Air Quality Guidelines for the protection of public health (WHO 2000, WHO 2014)

Pollutant	Averaging interval	Guideline value
PM₁₀	calendar year	20 µg.m^-3
PM₁₀	24 hours	50 µg.m^-3
PM_2.5	calendar year	10 µg.m^-3
PM_2.5	24 hours	25 µg.m^-3
Benzo[a]pyrene^a)		not recommended
NO₂	calendar year	40 µg.m^-3
NO₂	1 hour	200 µg.m^-3
O₃	8 hours	100 µg.m^-3
benzene^a)		not recommended
Pb		0.5 µg.m^-3
Cd^b)		0.005 µg.m^-3
As^a)		not recommended
Ni^a)		not recommended
SO₂	24 hours	20 µg.m^-3
SO₂	10 minutes	500 µg.m^-3
CO	1 hour	30,000 µg.m^-3
CO	8 hours	10,000 µg.m^-3

^a)These are human carcinogens therefore no safe level of the substance can be established. The WHO guideline value is not recommended. More information on the risks of cancer occurrence see WHO (2000).
^b) The recommended value for the prevention of further increase of cadmium in agricultural soils.