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No. 321: Ammonia Regulations in Northern Europe

Reinds, G.J., Bak, J., Bouil, L., Scheuscchner, T., Schaap, M., Hendriks, C., Hall, J., Rowe, E., Bealey, B., Braban, C., Dore, T., Banin, L., Smith, R., Dragosits, U., Vieno, M., Smits, N., Kros, H. & Wamelink, W. 2019. Ammonia Regulations in Northern Europe. Summary of policies and practises in France, Germany, the United Kingdom, the Netherlands and Denmark. Aarhus University, DCE – Danish Centre for Environment and Energy, 150 pp. Scientific Report No. 321. http://dce2.au.dk/pub/SR321.pdf


The main findings from the five main topics compared between the countries is summarized here. A more comprehensive summary can be found at the end of each of the main chapters of the summary report.

Monitoring and modelling nitrogen and ammonia deposition

Monitoring of ammonia in air and precipitation is carried out in all five countries, but results are in France and Germany not collated nationally. All countries model national deposition of pollutants including oxidized nitrogen and ammonia with complex models. Often, modelling is combined with measurements to compute the total fluxes. In general, countries use measurements of deposition to calibrate their deposition models. Uncertainties in modelled depositions are reported by four countries and are consistently in the range of 30-50%, but probably higher on local scale.

Ammonia-sensitive areas

Ammonia or nitrogen sensitive areas have been or will be assigned in three countries. In the UK such areas are not defined (yet), but an assessment has been made for the Annex 1 habitats based on their sensitivity. In the Netherlands, nitrogen sensitivity is based on the critical loads assigned to habitats. Natura 2000 areas that are nitrogen sensitive receive extra protection. In Denmark, both Annex 1 habitats and nature types in the Danish Nature Protection Act  are used and for both sets nitrogen sensitivity per type have been defined;  also about 1/3 of the forest area is considered nitrogen sensitive. In Germany and France, ammonia sensitive areas have not been assigned on national / federal level.

Effect of ammonia regulations

Regulation that effect farm location in relation to N sensitive areas are used in most countries. In UK a distance criteria is used as first step in assessing applications for expanding existing livestock sheds or building new ones. In a second step, assessment is based on critical load exceedances from the project in cumulation with other ammonia sources. A similar procedure is applied in NL were the AERIUS toolkit must be used to assess effects of new activities on N deposition on N-sensitive Natura 2000 areas. In Denmark, restructuring of agriculture has already resulted in a reduction of N deposition to N-sensitive areas reducing the area where critical loads are exceeded. In France, the Industrial Emission Directive is the main driver for ammonia reduction on farm level affecting 3400 farms.

In addition to local regulation, NOx control and general ammonia regulation e.g. BAT rules have helped controlling emissions. In Germany, deposition of NOx has decreased and deposition of NH3 has remained stable over the period 2000-2015. In the UK total N deposition decreased by 18% between 2004 and 2015. Also in Netherlands and Denmark, emissions of NOx and NH3 have been reduced between 2000 and 2015. This is reflected in a decline in NOx deposition but not in measured ammonia concentrations. 

Critical loads and levels

FR and DE use the simple mass balance to calculate critical loads for N and acidity. In Denmark, the SMB model is used for acidity and only for forest. NL uses a slightly different approach with application of a steady state version of the simple soil geochemical model VSD+. The criteria that are being used differ between countries, and often consist of a set of multiple criteria of ecosystem-specific criteria. Management of forest by removal of wood is included in the critical load calculations by all countries. DE, UK and NL also include management of grassland and heathland through e.g. grazing and/or mowing. Denmark and UK use empirical critical loads with different modifying factors

All countries are currently developing and applying methods to compute biodiversity-based critical loads. The approach is generally a geochemical model coupled with an empirical based plan occurrence model. NL is experimenting with VSD+PROPS[1] based methods, which DK is also testing. In France PROPS and EcoPlant are applied, Germany uses the Bern model[2], UK uses Madoc-MultiMove1 in which empirical critical loads are indirectly used.

Critical levels for NH3 are used in the UK and in DE within the framework of licensing new installations. In DK critical levels are used in habitat assessment (appropriate assessment) for larger industry.

Mostly the models and procedures follow the Mapping manual and empirical critical loads are mostly derived from reports published with the UNECE convention as well.

Concrete projects and the assessment of when and if critical loads for a certain ammonia sensitive area is exceeded

In Germany, critical loads are used in the emission control regulation as well as in the nature protection regulation; Different sets of critical loads and different approaches, to include general management such as mowing in the critical load calculations are being used in different federal states. For new emitting activities in Germany, limits are set to the concentration of ammonia at the emitter as well as to the total concentration of ammonia at the Nature area the new emitter affects.

In the UK Environmental permitting is carried out by, and is the responsibility of, separate regulating agencies for England, Wales, Scotland and Northern Ireland. Each Agency has its own procedures, methods and models. If the emissions from a process are judged to result in a likely significant effect on a designated site  then a detailed assessment is required. Management practices that may conflict with nitrogen deposition effects are taken into account at the detailed assessment stage.

NL has adopted a Programmatic Approach to Nitrogen (PAN). The PAN guarantees that Natura 2000 objectives will be met, by including effects of dedicated management and restoration plans for each N2000 area, as well as effects of extra N deposition.

In DK regulation of effects of ammonia on sensitive nature differentiates between different categories of nature where there for category 1 and 2 is a limit to the total allowable deposition from a single farm. For category 3, requirements can only be made, when e.g. the critical load is exceeded. In DK the Natura 2000 plans do not directly include measures to mitigate effects of too high nitrogen deposition. Normal N removal for managed ecosystems is though included in critical loads.

In UK, NL and DK detailed deposition models are used that use surface roughness to compute deposition fluxes. Local sources (new and existing) and local transport are covered in these models. In Germany, also local deposition should be taken into account in exceedance calculations. 

[1] A simple soil geochemical model coupled with an empirical based plan occurrence model

[2] The BERN model describes occurrence probabilities of plant communities, not individual plants.