Division 1 Sulphur dioxide

United Kingdom

	Health protection	Vegetation protection
Upper assessment threshold	60 % of 24-hour limit value (75 μg/m³, not to be exceeded more than 3 times in any calendar year)	60 % of winter critical level (12 μg/m³)
Lower assessment threshold	40 % of 24-hour limit value (50 μg/m³, not to be exceeded more than three times in any calendar year)	40 % of winter critical level (8 μg/m³)

Health protection

Vegetation protection

Upper assessment threshold

60 % of 24-hour limit value (75 μg/m³, not to be exceeded more than 3 times in any calendar year)

60 % of winter critical level

(12 μg/m³)

Lower assessment threshold

40 % of 24-hour limit value (50 μg/m³, not to be exceeded more than three times in any calendar year)

40 % of winter critical level

(8 μg/m³)