Appropriate measures to lower ammonia (NH3) emissions at farm level need to be implemented as the expansion of the dairy sector has negatively impacted air quality, according to the draft Clean Air Strategy.

The draft Clean Air Strategy identifies measures to reduce air pollution and promote cleaner air while delivering on national objectives.

Improved agricultural practices and a reduction in emissions are considered in the draft strategy. Minister for the Environment, Climate and Communications, Eamon Ryan commented:

“Air quality is closely associated with our climate and ecosystems. There is a clear correlation between the actions needed to lower air pollution and those needed to reduce greenhouse gas emissions.”

Emissions in agriculture are divided into greenhouse gases (GHGs) and air pollutants, of which Ammonia – a gaseous form of nitrogen – is considered an air pollutant, according to Teagasc.

Farm-level emissions

Agriculture accounts for 99% of total ammonia emissions in Ireland which steadily increased from 2014 to 2018, particularly driven by the expansion of the sector. However, application of mitigation measures to counteract this growth were not sufficiently enhanced, the draft stated.

Ammonia comes mainly from managing animal manures including slurry and from spreading synthetic fertiliser. However, according to the draft strategy, these agricultural activities also impact emission levels of nitrogen oxides (NOx) and none-methane volatile organic compounds (NMVOC).

These key activity areas “pose a significant challenge for Ireland in reducing overall pollutant emissions”, according to the draft strategy, as agriculture also accounts for 34.4% of total NOₓ emissions and 39.9% of NMVOCs in Ireland.

Image source: Environmental Protection Agency (EPA)

Between 2018 and 2019, ammonia levels decreased following initiatives at farm level in recent years including a reduction in crude protein of pig feed, low-emissions spreading of cattle and pig slurry and the introduction of clover into grass swards.

However, continuously exceeding the ammonia emission target under the EU National Emission Reduction Commitments Directive is an “area of concern”, the draft Clean Air Strategy stated.

Emission reduction measures

Several measures and strategies are already in place to reduce ammonia emissions including the Teagasc Ammonia MACC 2020; the Ag-Climatise roadmap for Ireland to meet GHG and air quality targets; and the Climate Action Plan including changes in animal diets, chemical nitrogen use and fertiliser management.

These strategies and measures must be adopted entirely for Ireland to be in compliance with the target for NH3 by 2022 and on track to reach the 2030 target, according to the Environmental Protection Agency (EPA).

Ag-Climatise and Climate Action Plan 2021 measures include the target of 60% of all slurry spread by low-emissions slurry spreading (LESS) by 2022; 80% by 2025; and 90% by 2027. Further significant measures are:

  • Reducing chemical nitrogen use to a maximum of 325,000 tonnes annually by 2030, with an interim target of 350,000 tonnes by 2025;
  • Prohibiting the use of urea, replacing it with protected urea by the end of 2023;
  • Requiring an incorporation and maintenance of clover (and mixed species) in all grassland reseeds, facilitating a reduction in chemical nitrogen usage;
  • Supporting the use of non-chemical nutrients such as bio-fertilisers;
  • Reducing the crude protein content of livestock feeding stuffs to minimise ammonia loss;
  • Genotyping the entire national herd by 2030 to facilitate the breeding of more environmentally efficient animals.

“Ag-Climatise represents the start of our ambition to ensuring there is no compromise between protecting the air that we breathe and the sector remaining at the forefront of globally sustainable food production systems,” the draft strategy stated.