Consultation on changes to guidance for assessing the impact of ammonia and nitrogen from agricultural developments

We have reviewed the guidance used to assess the potential environmental impact of emissions of ammonia and nitrogen from agricultural developments (referred to as GN020)

As a result of this review we are proposing the following changes to the guidance:

  • We will use the information produced for the Town and Country Planning Act EIA to determine a permit, and use the same thresholds where that information is available
  • We will use a variety of screening distances based on the type of development and the number of animal places proposed, reducing the distance for the smaller units and increasing it for the larger units.
  • We will produce a map of species and habitat locations around which extremely strict controls and detailed modelling is likely to be a requirement; this may include, but not necessarily be limited to, Natura 2000 sites.
  • We will remove the 1% screening threshold of insignificance for in-combination assessments.
  • We will use the critical level to inform whether the proposed development will harm the species or habitat.
  • We withdraw OGN 41 and only use GN 020 provided as web content
  • We will make the guidance accessible and collate all the required information into a single source
  • The guidance will be applicable to all developments that emit ammonia and require either planning permission or an environmental permit

What are we consulting on?

We would like to hear your views on the proposed changes listed above. Full details can be found in the Consultation document and the draft guidance document available for download below.

How to respond

In recognition of the challenges that the agricultural sector and other organisations face during the current Covid-19 pandemic we have extended the consultation by 3 months until the end of November, to allow more time for consideration.

Please email your comments by 30 November to:

or write to us at:

Natural Resources Wales
Ty Cambria
Newport Road
CF24 0TP

After this we will carefully consider all responses and make any necessary amendments to our draft guidance. We anticipate publishing the final guidance in January 2021. We will periodically review and update the guidance in future years.