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Revising and updating the inventory of ammonia emissions from UK agriculture, for 2005 and 2006. - AC0102

Agriculture accounts for c. 80% of the UK’s national emission of ammonia (NH3). These emissions originate from livestock housing, the storage, treatment and application of all types of animal manures and the use of inorganic fertilisers. Deposition of NH3 can lead to terrestrial and aquatic eutrophication and acidification. Ammonia is also a precursor to the secondary formation of ammonium, which contributes to the breaching of air quality standards for particulate matter across the UK and which has potentially significant human health effects. To limit such effects a protocol has been agreed under the UNECE Convention on the Long-Range Transport of Air Pollutants, the Gothenburg Protocol, which seeks to reduce emissions of four key pollutants including NH3. Defra therefore require an accurate inventory for NH3 emission from agriculture for annual submission to the EU (to determine if they are going to meet the agreed national target for the UK of 297 kt NH3 per year by 2010) and to provide a base from which to accurately predict reductions in NH3 emission as a result of implementing abatement practices.

Compilation of the annual inventory requires year-specific activity data (livestock numbers, fertiliser use, management practices) combined with robust emission factors (EF) for each emission source. The NARSES (National Ammonia Reduction Strategy Evaluation System) model, as developed under Defra project AM0101 (with continuing development under Defra project AM0133) will be used to derive the annual estimate of emission for official submission. An empirical estimate of annual emission, for comparison, will also be derived using the UK Ammonia Emissions Inventory (UKAEI) model (as previously used for official submissions under Defra projects AM0108 and AM0127). Defra project AM0123 (A collation and analysis of current ammonia research) provided an extensive review of the data used to generate EF for the current inventory models and concluded that the least robust EF, of most significance, were for buildings housing pigs and beef cattle on straw and for grazing by beef cattle and sheep. In addition, there needs to be a good understanding of the factors that control emission, in order to best represent changes in management practices or the adoption of mitigation strategies. This may be particularly important with the changes to livestock welfare regulations, leading to a greater surface area allowance for some livestock. Since NH3 emission is a surface area process, this change in area allowance could effect NH3 emissions considerably and the magnitude of this effect needs to be determined.

This project will provide the revised inventory estimates of NH3 emission from UK agriculture for the years 2005 and 2006 based on year-specific updates of activity data (livestock numbers, fertiliser use and management practices, all derived from existing annual surveys) and incorporating new experimental data into the inventory EF. It will focus in particular on the development of robust EF, through measurement, for buildings housing pigs and beef cattle on straw and for grazing beef cattle and sheep, identified as the least robust EF in the current inventory models. The impact of potential changes in livestock welfare regulations will be assessed as a desk study. The collation of improved activity data (i.e. beyond that provided by existing surveys), through more frequent and/or larger surveys providing better temporal and spatial resolution, will not be addressed in this project. The project will be led by IGER, with experts from ADAS, Royal Veterinary College, Cemagref and Silsoe Odours Ltd. acting as subcontractors. For ease of management this project has been divided into four work packages:

WP1. Updating the inventory of NH3 emission from UK agriculture for the years 2005 and 2006.
WP2. Ammonia emission measurements from pigs and cattle housed on straw.
WP3. Ammonia emission measurements from grazing livestock.
WP4. The impact of livestock welfare regulations on NH3 emissions (desk study)
The overall objective of the project is to produce an inventory of ammonia emission for UK agriculture for each of the years 2005 and 2006, required as the major part of the total UK ammonia emissions inventory for annual submission to the EC under the National Emissions Ceilings Directive. The project will provide new measurement data to increase the robustness of those emission sources identified as being the least robust. A secondary objective will be to assess the impact of potential changes in livestock welfare regulations on the inventory total.

Specific objectives are:

WP1. Updating smart ammonia inventory.
1.1. Revise and update the inventory of NH3 emissions from UK agriculture for the years 2005 and 2006.
1.2. Provide forward and backward projections of NH3 emissions from UK agriculture for the years 1990 – 2020.

WP2. Ammonia emissions from cattle and pig buildings on straw bedding.
2.1. Determine new, (and/or revised) robust EF for straw-based buildings housing key livestock classes (1 dairy house, 3 beef cattle houses and 4 finishing pig buildings).
2.2. Provide information on temporal variability of NH3 emissions (seasonal and weekly variation) from those buildings.
2.3. Provide improved understanding of the factors controlling variability of NH3 emissions: environmental (temperature, wind speed) and management (diet, stocking density, straw use).
2.4. To determine whether increasing the number of cattle within buildings will produce a pro rata decrease in the amount of NH3 emitted from those buildings.
2.5. Relate measured emission factors to published data and determine the impact on emission inventories (UKAEI and NARSES).
2.6. Make recommendations to reduce NH3 emissions from straw bedded buildings.

WP3. Ammonia emissions from grazing livestock.
3.1. Determine the best methodology for measuring ammonia emissions from grazing animals.
3.2. Determine new EF from grazing beef cattle and sheep.
3.3. Determine the variation in EF throughout the grazing season.
3.4. Provide new EF for WP1.

WP4. Impact of welfare regulations for pigs and laying hens on ammonia emissions.
4.1 Through literature review and current knowledge of emission factors – determine the impact of changes in laying hen welfare regulations on ammonia emissions.
4.2 Through literature review and current knowledge of emission factors – determine the impact of changes in pig welfare regulations on ammonia emissions.
4.3 Assess the impact of changes in welfare regulations on national ammonia emissions through scenario testing using NARSES and the UKAEI.
Project Documents
• FRP - Final Report : AC0102 evid4   (813k)
• ANX - Annex : AC0102 Appendix 1   (520k)
• ANX - Annex : AC0102 Appendix 2   (920k)
Time-Scale and Cost
From: 2006

To: 2008

Cost: £850,817
Contractor / Funded Organisations
Institute of Grassland and Environment Research (IGER)
Air Pollution              
Air Quality              
Environmental Protection              
Water Pollution              
Fields of Study
Agriculture and Climate Change