A new opinion has been issued by an Advocate General for the European Court of Justice (ECJ) with potential far reaching consequences for how Air Quality assessments are carried out under the Habitats Regulations.

A new ruling has been issued by the Advocate General Kokott (Coöperatie Mobilisation for the Environment UA and Others) with potential further far reaching consequences for how Air Quality assessments are carried out in the UK. The case was brought in the Netherlands where in 118 of their 162 Natura 2000 sites (SACs/SPAs) there is an overload of nitrogen deposition. The most important source of that nitrogen is agriculture. The nitrogen overload in protected sites affects in particular habitat types whose vegetation is specialised in nitrogen deficiency. The protection of these ecological features is therefore a particular challenge and also capable of hampering economic developments that cause nitrogen deposition.

The case requested an opinion from the Advocate General in respect of the permitting arrangements at a number of farms. In particular, a range of questions were asked of the Advocate General which are considered in her opinion. including whether in the assessment under Article 6(3) of the Habitats Directive account may be taken of certain measures and developments which are not directly related to the respective plan or project to be assessed. In particular, the Raad van State (Council of State) asks whether an expected autonomous decrease of nitrogen emissions may be taken into account. In addition, it asks about measures which reduce nitrogen emissions from other sources and restoration measures in sensitive habitats of protected sites which are intended to create room for further nitrogen deposition.

In considering these questions the Advocate General concludes that:

– measures to reduce nitrogen deposition from other sources,

– restoration measures to improve nitrogen-sensitive habitat types in the sites concerned, and

– the autonomous decrease in nitrogen emissions

can establish the compatibility of additional nitrogen deposition in protected sites with Article 6(3) of the Habitats Directive only if it is already definitively established at the date of the authorisation that the total load on the site from nitrogen deposition falls below the threshold for the integrity of the site being adversely affected. On the other hand, it is not sufficient, for the purposes of approval of additional nitrogen deposition, if deposition declines overall, but the land in question is still overloaded with nitrogen. Mere forecasts regarding the future effects of those measures and the expected decrease in nitrogen emissions may not be taken into account in the decision on the approval of additional nitrogen deposition.

This advice is likely to have far reaching consequences for the methodological approach to the assessment of air quality effects in England. In particular, it is highlighted that this is at odds with Natural England’s recent guidance entitled ‘Natural England’s approach to advising competent authorities on the assessment of road traffic emissions under the Habitats Regulations (NEA001)’ here June 2018.

It should be noted that the role of the Advocate General is to provide independent and impartial opinions concerning the Court’s cases. The opinions of the Advocates General are advisory and do not bind the Court, but they are nonetheless very influential and are followed in the majority of cases. The Court is due to rule on this case in due course.

Other noteworthy extracts within the opinion include:

  1. The fact presented by the Raad van State (Council of State) that nitrogen deposition is declining overall is thus to be welcomed but is inevitably insufficient in itself. Rather, Article 6(2) and (3) of the Habitats Directive requires that the load level be reduced such that a favourable conservation status can be achieved in the long term.


  1. In this regard, it seems difficult, if not impossible, to accept values that are higher than the critical loads. These are intended to define scientifically-based load limits for vegetation types or other protected assets, compliance with which means that pollutant deposition is not expected to have significant harmful effects even in the long term. Scientists have identified such critical loads for nitrogen for the protected habitat types under the Habitats Directive in the Netherlands.


  1. Furthermore, it would also appear to be necessary to consider to what extent the individual protected habitats have been exposed to an overload of nitrogen deposition for a considerable time. On the one hand, it would have to be presumed that the status of the habitats has already changed adversely as a result of such deposition, in particular as regards the plant species present. On the other hand, there is probably an initial overload of nitrogen which must be removed or otherwise eliminated before the habitats can be developed in the light of the conservation objectives for the site. It might therefore be necessary, until the removal of existing nitrogen reserves, to permit even less additional nitrogen deposition than envisaged in the critical loads (our emphasis).


  1. The competent national court will have to review, in the light of these considerations, whether the critical loads or other values are so scientifically sound that, if they are complied with, all reasonable scientific doubt can be excluded that the integrity of the sites concerned is not adversely affected.


  1. This is clearly illustrated by the example of nitrogen deposition. It is not sufficient to reduce this by a certain amount, such as 1 kg N/ha/yr, in order to permit the same degree of additional deposition if the protected habitat as a whole is still overloaded with nitrogen. Additional deposition can be permitted only if the total load, including this, is sufficiently small that it does not adversely affect the integrity of the site.