The Air Quality Standards (Wales) Regulations 2010 No. 1433 (W. 126)

Regulations 18 and 23(1)

SCHEDULE 5 E+W Critical levels for the protection of vegetation

Sulphur dioxide

Averaging period	Critical level
Calendar year and winter (1 October to 31 March)	20 μg/m3

Oxides of nitrogen

Averaging period	Critical level
Calendar year	30 μg/m3 NOx