Ammonia assessments for developments that require a permit or planning permission

Why are we worried about ammonia? 

Ammonia can have a significant effect on human health and the environment. Most but not all ammonia emissions come from agriculture (over 90%) and adversely affect the environment close to the release point. Plants that are sensitive to ammonia have evolved in a low nutrient environment and are able to utilise very small concentrations of nutrient.

When these plants encounter higher levels of ammonia they cannot grow and tend to die. The loss of these sensitive plants leads to a change in the way the ecosystem functions and affects the food available in that ecosystem. In turn this has an adverse effect on the whole food web, leading to a loss of species. 

Ammonia is a very reactive gas and forms other compounds in the air that become pollutants away from the source. This includes the very fine particulate matter pollution that forms in urban areas from the interaction between nitrogen oxides and ammonia.  

What to do if your development is likely to release ammonia

If your development is listed below or you think there is a possibility it will release ammonia, then you will need to provide information to help us, or planning authorities, assess if your development can operate without harming the environment. 

These pages will help take you through the process required to provide that information. 

What type of developments release ammonia into the air? 

The main type of developments that release ammonia are listed below, if your type of development is listed here, then we advise you use this guidance in your application or risk having that application rejected. 

Poultry Farming: includes chickens, turkeys, guinea fowl, ducks, geese, quails, pigeons, pheasants and partridges reared or kept in captivity for breeding, the production of meat or eggs for consumption, or for restocking supplies of game 

  • Pig farming: all types 
  • Dairy farming: all types 
  • Beef farming: all types 
  • Anaerobic digestion and associated activity: open storage of feedstock and digestate (there is no need to carry out an assessment for the digestor or from enclosed tanks or if the capacity is below that listed in the screening criteria below)
  • Slurry stores: all types 
  • Use of urea for nitrogen oxide reduction: this is for point sources of ammonia, emission factors are not suitable and you must move directly to detailed modelling. 
  • Landspreading: if you are required to carry out a habitats regulation assessment (HRA), Environmental Impact Assessment (EIA), or are within close proximity to a sensitive site then landspreading must be included in the assessments of impacts.   

Once you have decided if your development emits ammonia then depending on the background level concentrations you can decide whether to carry out a screening assessment or move directly to a detailed modelling assessment.

Screening or detailed modelling? 

In some areas of Wales, the amount of ammonia is already at, or above the levels that are harmful to some of the species in the sensitive sites. If the background level is at or above the critical level, then you must carry out detailed modelling.  

If the background level of ammonia is below the critical level, then you can carry out a screening assessment. 

Background values of ammonia 

You will need to know how much ammonia there is already at a sensitive site. These are known as the background values. 

You can find out background values from the Air Pollution Information Service (APIS) website 

What happens if I am improving things? 

If you are making changes that will result in the lowering of ammonia emissions or a decrease in risk of pollution occurring then please state this clearly in your application and go to ‘Applications that reduce the impact or risk of pollution' to understand what you need to do to ensure the LA and NRW have the correct information to consider this.

Read about ammonia assessments initial screening and evidence gathering

Last updated