Nitrogen deposits from construction activities (and the potentially required permit for such deposits on nature conservation areas) is an important element for real estate projects in The Netherlands. In short: when performing building activities and/or using a property, a permit under the Nature Conservation Act (Wet natuurbescherming) may be required for nitrogen deposits that may negatively affect protected Natura 2000 areas. To determine whether a deposit that rises to the level of requiring a permit occurs, developers must perform a so-called AERIUS-calculation. This obligation applies to both the building as well as the realization phase of a project, meaning two separate calculations must be performed.

The AERIUS-calculations are performed by technical experts taking into account various factors, such as traffic movements. The model for the AERIUS-calculation is developed and made available by the National Institute for Public Health and the Environment (RIVM).

Recently, the new AERIUS-model 2022 has been published (see the website of the RIVM, in Dutch and English). As of 26 January 2023, the AERIUS-model 2022 must be used for pending permit applications, pursuant to the Nature Conservation Scheme (Regeling natuurbescherming). If the competent authority has not yet made a formal decision on a permit application, a new calculation must be performed, even if the results of the former calculation indicated that no increase of nitrogen deposits occurs as a result of the project.