What is nitrogen and can we control it?

What exactly is nitrogen?

Nitrogen is an element that is found in abundance on earth. The air we breathe consists of nitrogen for a large fraction. This is nitrogen in its pure, non-reactive and harmless form (N₂). A small part of the nitrogen on earth (and in the air) is found in the form of reactive nitrogen. These are chemical compounds that contain nitrogen and are indispensable as nutrients for nature.

However, in excess, reactive nitrogen can have a harmful effect. The main reactive nitrogen compounds that humans emit into the atmosphere are ammonia (NH₃) and nitrogen oxides (NOx). These emissions cause a deterioration of air quality before they settle.

When a substance settles from the air onto the ground, this is called deposition. Not everything that we emit is deposited in the same location. Nitrogen oxides (NOx), in particular, can travel over great distances blown by the wind and may settle hundreds of kilometres away. Ammonia (NH₃) is deposited closer to its emission source than NO_X.

Too much nitrogen causes problems for nature

The European Habitats Directive requires EU Member States to ensure that, as far as possible, any decline in the biodiversity of important plant and animal species in Natura 2000 areas is prevented.

Since the Dutch Council of State’s judgment in 2019, it has only been permitted to carry out economic activities if they do not harm or cause any further harm to Natura 2000 areas. However, damage due to nitrogen deposition is already so great in these areas that action is needed in the short term to restore nature and allow new economic activities to be pursued in the Netherlands. As a result, the country finds itself in gridlock and the government is looking for solutions to find a way out of this impasse.

Getting a grip on nitrogen

TNO agrees that the Netherlands needs to reduce its nitrogen emissions and advocates enforcing an absolute, gradually decreasing emissions budget per region. Ensuring effective control at the level of individual emission sources is important here, which will require an expanded package of control instruments, such as innovation, monitoring, and certification.

To allow steps to be taken as quickly as possible, we are proposing solutions based on a differentiated approach: for the short and medium term, as well as for locations close to and further away from Natura 2000 areas. Emissions of ammonia and nitrogen oxides are not entirely interchangeable. To make the overall approach less legally vulnerable, we are therefore advocating separate emissions budgets for these substances. Download and read the vision paper below.