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Acidification is commonly associated with atmospheric pollution arising from anthropogenically derived sulphur (S) and nitrogen (N) as NOx or ammonia, which e.g. occur during the production of food. Anthropogenically derived pollutant deposition enhances the rates of acidification, which may then exceed the natural neutralising capacity of soils.


Figure 6. Illustration of acidification of an aquatic environment

The environmental impacts of acidification are one of the major contemporary environmental issues globally. When acids are emitted, the pH factor falls and acidity increases, which for example can involve widespread decline of coniferous forests and dead fishes in lakes in Scandinavia. The acidification potential is calculated in SO2-eq. (see Table 4).

Table 4. Equivalent factors for GWP, eutrophication and acidification

GWP equivalent factors:
1 kg carbon dioxide (CO2) 1 kg CO2-eq.
1 kg methane (CH4) 25 kg CO2-eq.
1 kg laughing gas (N2O) 298 kg CO2-eq.
Eutrophication equivalent factors:
1 kg nitrate (NO3) 1 kg NO3-eq.
1 kg ammonia (NH3) 3.64 kg NO3-eq.
1 kg phosphate (PO43-) 10.45 kg NO3-eq.
Acidification equivalent factors:
1 kg sulphur dioxide (SO2) 1 kg SO2-eq.
1 kg ammonia (NH3)> 1.88 kg SO2-eq.