When the air pollutants sulphur dioxide and nitrogen oxides are deposited back to the ground, they contribute to acidification of soils and surface water, damaging terrestrial and aquatic ecosystems.
In this study, records of over 50 forest monitoring sites across
For both sulphur dioxide and nitrogen dioxide, air concentrations decreased. The total deposition of sulphur declined in the majority of the forest monitoring sites during the 12 year period 1997-2008, and rates varied between north and south. Deposition was greatest in the southwest, and gradually diminished towards the northeast.
Over the study period, sulphur deposition rates decreased the most in southwest
Patterns of nitrogen deposition, measured on open field, were similar to that of sulphur deposition across
The concentration of sulphur in soil water tended to be higher in the south of
Despite the reduction of sulphur in soil water and although some southern sites showed recovery from acid conditions during the period 1996/97- 2007/08, many other sites showed little change in acidity, indicating slow progress in recovery and return to less acidic soil conditions.
The increased levels of nitrogen deposition have resulted in higher levels of nitrogen found in soil water. The southwest of
Source: Karlsson, G.P., Akselsson, C., Hellsten, S., Karlsson, P.E. (2011) Reduced European emissions of S and N - Effects on air concentrations, deposition and soil water chemistry in Swedish forests. Environmental Pollution. 159: 3571-3582.