Critical Load/Level Values
30 µg NOX (as NO2) m-3 annual mean; 75 µg NOX (as NO2 ) m-3 24-hour mean
Status
UNECE 2004
Habitat/Ecosystem Type
all vegetation categories
Description
The concentration units are referenced as if all the NOX were in the form of NO2 (see Unit Conversion). Nitrogen oxides are known to have greater adverse effects in the presence of SO2 and O3, and hence the critical level should apply where these pollutants are close to their critical level too.
Reliability
Uncertainty: quite reliable i.e. the results of some studies are comparable