In northwest Europe nitrogen deposition levels form one of the main barriers to achieving European nature conservation targets. To solve the issues around nitrogen and nature, the Netherlands has developed new policy. The Integrated Approach to Nitrogen (PAS) ensures the achievement of the Natura 2000 objectives, while kick-starting the deadlocked permit issuing process for new economic activities – using an inter-governance approach, across all sectors and nature sites. The PAS has been implemented in mid 2015.

AERIUS is the online calculation tool of the PAS. It calculates both emissions and deposition levels for nature areas, caused by new or expanding economic activity. Since the implementation of the PAS, project initiators are legally obligated to use AERIUS to calculate the nitrogen impact of their projects. The calculation results then serve as the foundation for permit applications, to comply with the Nature Conservation Act 1998. This applies to all nitrogen emitting sectors: agriculture, industry, and traffic & transport.

The AERIUS tool is also used to monitor the monitor the reduction of nitrogen deposition as well as the continuity of the effect of ecological restoration measures.

The development of such a calculation tool is a challenging task. There are important preconditions attached to AERIUS. The tool not only has to represent the scientific “state of the art”, it should also be very user-friendly, since is it going the be used by a broad range of government employees, scientists, professionals, and the public.

The application Stack is Java GWT and OpenLayers for the web based front-end, Java applications for backend, PostgreSQL with PostGIS as database, GeoServer for our own geospatial maps, RabbitMQ as message queuing service. Swagger for the API implementation. OpenCL for our implementation of one of the scientific calculation models.

The AERIUS products are 3 web based applications: Calculator, Register and Monitor.

AERIUS Calculator is used for calculating nitrogen emissions from economic activity and their deposition in Natura 2000 areas. In the web based application users have direct visible feedback on a map about their effects. Users can export a pdf document containing all necessary data for a permit application. For some situations it also possible to make a notice directly from with the application.    

Competent authorities use AERIUS Register to manage the already issued and the available room for development under the PAS.

Monitor monitors the implementation and the results of the PAS. Monitor provides insight, among other things, into the trend in nitrogen deposition and the available room for development and deposition.

On the backend a number of dedicated applications are running to create the pdf documents and perform the calculations. All these applications communicate via an AMQP message bus which makes it easy to scale depending on the load and also makes it fail safe. If an application would crash the job will be performed by the next application. The backend is managed by a task manager that manages the load. Because certain calculations can cause a heavy load the task manager controls priorities making sure certain processes won't cause the system to choke. This architecture resembles a micro services architecture, but was designed before that architecture became popular.

The application consists in dedicated applications that are decoupled via message queuing. This architecture makes it possible to scale if the load on the system becomes higher. It resembles a micro service architecture.

There is an API interface available with which third parties can integrate directly with the AERIUS calculation services and also validate AERIUS IMAER data. The API is built with Swagger which makes it easy to extend the service in a programming language preferred by the third party.

The software is completely build on open source technologies and tries to use as much as possible existing products. The maps in the front-end are created with OpenLayers and for maps based on our data we use GeoServer, and our base layer uses the Dutch PDOK map service ( For application intercommunication we use AMQP message queuing with RabbitMQ. The AERIUS API is built with Swagger.

For authentication we reuse the existing technologies Apache Shiro and the Dutch government authentication for companies: e-Herkenning.

The information model used by users of AERIUS our own information model IMAER. It is an extended Geography Markup Language (GML) standard. IMAER has become part of the Dutch NEN3610 standard. Data specific for AERIUS is available as open data via a WFS service.


Netherlands: three ministries (Economic Affairs, Infrastructure and the Environment and Defense) and all the twelve provinces.

The national government and the twelve provinces are collaborating within the policy framework the 'Integrated Approach to Nitrogen' to reach the Natura 2000 goals set by the EU Habitat and Bird directive. Together the government parties commission the development of the AERIUS applications. Therefore they are assembled in a Change Decision and Change Advisory board where all parties are represented. The National Institute for Public Health and the Environment (RIVM) is responsible for the actual development of AERIUS.

By means of a pre-discovery project in collaboration with the RIVM, the UK government, lead by JNCC and Natural England, is evaluating the potential use of AERIUS within the UK.

AERIUS combines and incorporates a lot of available information and streamlines it to either comprehensive information to make ecological assessments of the required documentation for issuing a permit.

There are two main benefits of the AERIUS product. First AERIUS provides comprehensive and standardized information to make an ecological assessment for N2000 sites. Therefore, more time is spend evaluating the facts rather than collecting them from various sources with varying uncertainties. Also ecological assessments are comparable across the nation for all N2000 sites. AERIUS is also used as a communication instrument when the ecological assessments are made publicly.

Secondly, AERIUS is used for requesting as well as issuing permits. By implementing AERIUS this process is not only much more efficient but also more transparent. The time and energy, and therefore the costs, of the permit issuing process are about 50% of the situation before AERIUS was implemented. There is also less discussion about the calculation results, which leads to fewer lawsuits.