Environment Agency
December 4
15:03
2024
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Use these emission factors for:
- carrying out ammonia assessments as part of your intensive farming permit application
- calculating your annual emissions for reporting to the pollution inventory
This guidance supports the intensive farming risk assessment for your environmental permit guide.
Ammonia emission factors for pigs
Sows (including gilts)
| Housing type | Ammonia emission factor (kg ammonia per animal place per year) | Crude protein content of animal diet (%) |
|---|---|---|
| Fully slatted floor | 2.94 | 15.8 |
| Solid floor (straw based system) | 3.29 | 15.8 |
| Partially slatted floor with reduced manure pit | 2.06 | 15.8 |
| Fully slatted floor with frequent slurry removal (a minimum of once weekly removal achieved through scraping, pumping or flushing) | 2.21 | 15.8 |
Farrowers (including piglets)
| Housing type | Ammonia emission factor (kg ammonia per animal place per year) | Crude protein content of animal diet (%) |
|---|---|---|
| Fully slatted floor | 4.62 | 15.8 |
| Solid floor (straw based system) | 5.41 | 15.8 |
| Fully slatted floor or partially slatted floor (with a combination of water and manure channels) | 3.23 | 15.8 |
Weaners (between 7kg and 30kg live weight)
| Housing type | Ammonia emission factor (kg ammonia per animal place per year) | Crude protein content of animal diet (%) |
|---|---|---|
| Fully slatted floor | 0.443 | 21 |
| Fully slatted floor with frequent slurry removal (a minimum of once weekly removal achieved through scraping, pumping or flushing) | 0.332 | 21 |
| Solid floor (straw based system) | 0.254 | 21 |
| Partially slatted floor with reduced manure pit | 0.332 | 21 |
Production pigs (over 30kg live weight)
| Housing type | Ammonia emission factor (kg ammonia per animal place per year) | Crude protein content of animal diet (%) |
|---|---|---|
| Fully slatted floor | 2.813 | 18 |
| Fully slatted floor with frequent slurry removal (a minimum of once weekly removal achieved through scraping, pumping or flushing) | 2.11 | 18 |
| Solid floor (straw based system) | 1.888 | 18 |
| Partially slatted floor with reduced manure pit | 2.11 | 18 |
Ammonia from pig slurry storage
| Slurry store or lagoon cover type | Ammonia emission factor (kg ammonia per m2 per year) |
|---|---|
| Store or lagoon with no cover | 1.13 |
| Store or lagoon with a rigid cover | 0.23 |
| Store or lagoon with a floating cover | 0.45 |
| Store or lagoon with a low tech cover (such as a natural crust or straw cover) | 0.68 |
Ammonia from pig manure storage
| Manure storage | Ammonia emission factor (kg ammonia per tonne per year) |
|---|---|
| Manure heap | 0.85 |
Ammonia emission factors for poultry
Broilers
| Housing type | Ammonia emission factor (kg ammonia per animal place per year) | Crude protein content of animal diet (%) |
|---|---|---|
| Indoor rearing | 0.024 | 20.3 |
| Free range rearing | 0.03 | 20.3 |
Layers
| Housing type | Ammonia emission factor (kg ammonia per animal place per year) | Crude protein content of animal diet (%) |
|---|---|---|
| Enriched caged systems with belt removal | 0.048 | 15.3 |
| Non-caged system single tier | 0.137 | 15.3 |
| Non-caged system multi-tier with belt removal | 0.073 | 15.3 |
Free range poultry
For typical free range systems, in a 24-hour period it is estimated that birds spend:
- 10% of time on the range
- 90% of time within the housing
The following table shows how the standard free range emission factors have been calculated for screening and modelling purposes. You should use the combined housing and ranging factors for pollution inventory reporting.