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 (NO_x), 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 (NO_x), ammonia (NH₃), and sulfur dioxide (SO₂).