Critical Load/Level Values

20 µg SO2 m-3 annual mean and half-year (Oct-March) mean.

Status
UNECE, 2004
Habitat/Ecosystem Type
Forests and semi-natural vegetation
Description

Low temperature appears to enhance the negative effects of SO 2 , and the lower critical level of 15 µg SO 2 m-3 is used where the effective temperature sum (ETS) (i.e. the sum of temperatures) above 5 o C is below 1000 degree days (d.d) (Ashmore et al., 1994).

Reliability
quite reliable i.e. the results of some studies are comparable