Ecosystem quality


The deposition of nutrients (namely, nitrogen and sulfur) in acidifying forms may cause changes in soil chemistry and subsequent acidification of the soil. Here, we assess the environmental impact of nitrogen oxides (NOx), ammonia (NH3), and sulfur dioxide (SO2).


Cause-effect pathway


We propose a method to assess the acidification impact on vascular plant species, which are caused by the emissions of nitrogen oxides (NOx), ammonia (NH3), and sulfur dioxide (SO2).



Modeling approach


The model consists of two parts. The fate factor models the atmospheric transport of the emitted pollutants and their subsequent impact on soil pH, while the effect factor models the sensitivity of the receiving ecosystem to soil acidity. The effect factor is based on the decline in richness of vascular plants.



Value choices


The time horizon for this impact category is not relevant since it is assumed that the impact occurs at the moment of emission of the substances, i.e. after the deposition of the substances.



Spatial variability


The coverage of the model is global. The spatial resolution of the model is 2.0° x 2.5°.



Characterisation factors


Characterisation factors are provided for emissions of nitrogen oxides (NOx), ammonia (NH3), and sulfur dioxide (SO2).


Azevedo, L. B., van Zelm, R., Hendriks, A. J., Bobbink, R. and Huijbregts, M. A. J. (2013). Global assessment of the effects of terrestrial acidification on plant species richness. Environmental Pollution 174(0): 10-15.

Roy, P.-O., Azevedo, L. B., Margni, M., van Zelm, R., Deschênes, L. and Huijbregts, M. A. J. (2014). Characterization factors for terrestrial acidification at the global scale: A systematic analysis of spatial variability and uncertainty. Science of The Total Environment 500–501: 270-276.

Roy, P.-O., Deschênes, L. and Margni, M. (2012a). Life cycle impact assessment of terrestrial acidification: Modeling spatially explicit soil sensitivity at the global scale. Environmental Science & Technology 45(15): 8270–8278.

Roy, P.-O., Deschênes, L., Margni, M. and Huijbregts, M. A. J. (2012b). Spatially-differentiated atmospheric source-receptor relationships for nitrogen oxides, sulfur oxides and ammonia emissions at the global scale for life cycle impact assessment. Atmospheric Environment 62: 74-81.