Ammonia Emission Estimates

There have been a number of improvements to the ammonia (NH3) emission estimates since the 1998 inventory. An in-depth study into the non-agricultural sector has enabled a number of sources to be better characterised, allowing emissions estimates to be included in more detail. Emissions from the agricultural sector are taken directly from the agricultural NH3 inventory compiled for MAFF (now a part of DEFRA) each year by a consortium of organisations. There is on-going work to improve the NH3 emission estimates from both agricultural and non-agricultural sources.

Table 5.11 UK Emissions of Ammonia (ktonnes)

1970

1980

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

1999%

BY UN/ECE CATEGORY1

Comb. in Energy Prod.

Public Power

0

0

0

0

0

0

0

0

0

0

0%

Other Comb. & Trans.

0

0

0

0

0

0

0

0

0

0

0%

Comb. in Comm/Inst/Res

Residential Plant

6

6

6

6

5

4

4

4

4

4

1%

Comm/Pub/Agri Comb

0

0

0

0

0

0

0

0

0

0

0%

Combustion in Industry

Iron & Steel Comb.

0

0

0

0

0

0

0

0

0

0

0%

Other Ind. Comb.

0

0

0

0

0

0

0

0

0

0

0%

Production Processes

8

7

8

8

7

7

8

6

9

5

1%

Solvent Use

1

1

1

1

1

1

1

1

1

1

0%

Road Transport

1

1

2

4

6

9

12

14

17

19

6%

Waste

Landfill

5

5

5

5

5

5

5

5

5

5

1%

Non Landfill Waste

6

7

7

7

8

8

8

8

8

7

2%

Agriculture

Animal Wastes

258

247

244

246

249

244

244

245

250

248

71%

Non Livestock Agricul.

54

58

44

39

37

32

26

30

29

32

9%

Nature

Wild Animal Wastes

13

13

13

13

13

13

13

13

13

13

4%

Humans

8

8

8

8

8

8

8

8

8

8

2%

Other Animal Wastes

6

6

6

6

6

6

6

6

6

6

2%

By FUEL TYPE

Solid

6

6

5

6

5

4

4

4

3

4

1%

Petroleum

1

1

2

4

6

9

12

14

17

19

6%

Gas

0

0

0

0

0

0

0

0

0

0

0%

Non-Fuel

359

353

337

334

334

324

319

323

329

325

93%

TOTAL

365

360

344

343

345

337

335

341

349

348

100%

1 See Appendix 4 for definition of UN/ECE Categories

Ammonia emissions are dominated by agricultural sources with emissions from livestock and their wastes comprising 71% of the total emission. These emissions derive mainly from the decomposition of urea in animal wastes and uric acid in poultry wastes. Emissions depend on animal species, age, weight, diet, housing systems, waste management and storage techniques. Hence emissions are affected by a large number of factors which make the interpretation of experimental data difficult and emission estimates uncertain (DOE, 1994). The other agricultural sources included are emissions from fertiliser use, crops and decomposition of agricultural vegetation. These are particularly uncertain owing to the complexity of the processes involved.

Sutton et al (2000a, 2000b) give estimates of a number of non-agricultural emission estimates, some of which have been incorporated here. The non agricultural sources comprise a number of diverse sources and equal 20% of the total. However, emission estimates for these sources are very uncertain due to a lack of data. Emissions of ammonia from road transport although relatively small are increasing as a result of the increasing number of three way catalysts in the vehicle fleet. Detailed consideration has been given to the current emissions and potential future emissions from non-agricultural sources in Handley et al (2001).

Figure 5.18 Ammonia Emissions Profile

 

Figure 5.19, Spatially Disaggregated UK Emissions of NH3