One target of the European Commission’s zero pollution action plan is to reduce the area of ecosystems in the EU at risk of eutrophication caused by atmospheric nitrogen deposition by 25% by 2030, compared to 2005. The total area where nitrogen deposition exceeded the so called critical loads for eutrophication - the scientific parameter that measures such a risk - fell by 10% between 2005 and 2021. Initiatives such as the national emission reduction commitments directive, farm to fork strategy and biodiversity strategy for 2030 are key frameworks to further reduce the risk of eutrophication in ecosystems.

Figure 1. Risk of eutrophication measured as exceedance of critical loads of nitrogen deposition in Europe, in 2021

Risk of eutrophication measured as exceedance of critical loads of nitrogen deposition in Europe, in 2021

The quantitative assessment of nitrogen deposition on terrestrial and aquatic ecosystems is estimated as critical loads. When the deposition of nitrogen exceeds such critical loads, it can lead to eutrophication and biodiversity loss. Nitrogen deposition is mainly caused by ammonia (NH3) from agricultural activities and nitrogen oxides (NOx) from combustion processes.

The zero pollution action plan (ZPAP) aims to reduce pollution in the EU to levels not harmful to human health or ecosystems. ZPAP’s target 3 sets a clear objective to reduce the area of ecosystems where nitrogen deposition exceeds critical loads by 25% by the year 2030, compared to the levels in 2005. This indicator monitors progress towards meeting this target and is also relevant for the follow-up to the Air Convention review of the Gothenburg Protocol (2019-2022), indicating a coordinated effort to address air pollution.

The European Commission's Third Clean Air Outlook provides valuable analyses of the progress and prospects of achieving the target of reducing ecosystems at threat of eutrophication by 25% and identifies potential policy adjustments to meet the goal by 2030. It emphasises the importance of continuous efforts to effectively combat air pollution and its impacts on ecosystems. The baseline scenario, which assumes no additional measures beyond current efforts, predicts a reduction of only 20% in affected ecosystems by 2030, compared to 2005. While this represents progress, it falls short of the 25% reduction goal for all affected areas, which would then still represent 983,500 km2. Furthermore, the analyses highlight the importance of focusing on specific actions to address ammonia emissions from agriculture, particularly through more efficient management and application of manure from cattle, pigs, and poultry, as well as mineral fertilisers to reduce ammonia emissions. The analyses also suggest that future stricter air quality standards would enable the EU to meet the ecosystem target by the 2030 deadline (see the underpinning study for the Third Clean Air Outlook).

The implementation of measures intended to achieve the 50% reduction in nutrient losses set out in the farm to fork strategy  and the nature restoration targets of the biodiversity strategy can also contribute to reducing atmospheric nitrogen deposition.

Figure 2. Evolution of the risk of eutrophication in European countries, measured as exceedance of critical loads of nitrogen deposition, in 2005 and 2021

Since 2005, the critical loads for nitrogen were exceeded in almost all EU Member States. Exceedances are attributed to both reduced nitrogen compounds from agricultural activities and oxidised nitrogen from combustion processes.

In 2021, emissions of oxidised nitrogen (NO2, nitric acid and nitrate-containing particles) was highest in Belgium, northern Germany, northern Italy, the Netherlands and Poland (see 2023 EMEP Report).

The agriculture sector accounted for 94% of all reduced nitrogen deposition in EU-27 Member States, from which about 72% of emissions came from livestock in 2021. Reduced nitrogen is deposited in ecosystems as NH3 and ammonium (NH4+). Deposition was highest in Belgium, parts of France, northern Germany, northern Italy, the Netherlands and Poland (see 2023 EMEP Report).

In 2021, the highest exceedances of nitrogen critical loads were found in the Po Valley in Italy, on the border areas between the Netherlands and Germany, along the border between Denmark and Germany and in north-eastern Spain. However, exceedances hot spots can also be found in the Netherlands and its border areas with Belgium.