Nature of the problem (science/management/policy):
Reactive nitrogen has both positive and negative effects on ecosystem and human health. Reactive nitrogen is formed through the use of fossil fuels releasing large amounts of nitrogen oxides into the atmosphere and through the production of ammonia by the Haber-Bosch process and using it in agriculture to increase our food, feed and fuel production. While the use of nitrogen as a fertilizer has brought enormous benefits, losses of fertilizer nitrogen and combustion nitrogen to the environment lead to many side effects on human health, ecosystem health, biodiversity and climate.
Approaches:
The European nitrogen problem is placed in a global perspective, showing the European nitrogen fixation, transport and environmental impacts compared to different regions of the globe.
Key findings/state of knowledge:
An overview is provided of the nitrogen issues and challenges in Europe and places them in a broader global context. Europe is one of the leading producers of reactive nitrogen, but it is also the first region in the world where the issue was recognized and in some parts of Europe the reactive nitrogen losses to the environment started to decrease.
There is a clear policy on reducing nitrogen oxide emissions that led to reductions by implementation of end of pipe technology.
Fertilizer production and use decreased in Europe in the early 1990s, in particular, due to the economic recession in the Eastern part of Europe. Currently, the fertilizer use in EU25 is about 12 Mton, which is 4 Mton lower than in the 1980s and gradually increasing. The nitrogen use efficiency of nitrogen in the EU, defined as the net output of N in products divided by the net input is about 36%. This is lower than the world average (50%) as fertilization rates are much higher.
Major uncertainties/challenges:
The effects related to losses of nitrogen in Europe include the exceedance of critical loads and the resulting biodiversity loss, ground water pollution and eutrophication of ecosystems; eutrophication of open waters and coastal areas resulting in algae blooms and fish kills; increased levels of NOx and aerosols in the atmosphere resulting in human health impacts and climate change; and the increased emissions of the greenhouse gas nitrous oxide resulting in climate change. Nitrogen also affects the biogeochemical cycles of other components such as carbon.
Recommendations (research/policy):
The complexity of multi-pollutant ¿ multiple-effect interactions is a major hurdle to improving public awareness.JRC.H.1-Water Resource
