Publication Date:
2007-03-01
Description:
Ammonia (NH3) emission from agriculture is an environmental and health concern in many nations, and has trans-border impacts. Direct toxicity, terrestrial eutrophication and production of inhalable aerosols (〈 2.5 µm diameter) are the specific concerns. Canada, among other northern hemisphere nations, has computed a national inventory of NH3 emissions, and a new emission inventory estimate is being prepared jointly under the National Agri-Environmental Health Analysis and Reporting Program (NAHARP) and National Agri-Environmental Standards Initiative (NAESI). However, there has been a rapid evolution in the models used, and a concomitant change in the NH3-specific data required. This paper compares several model structures and options using Monte Carlo simulation and sensitivity analysis methods. The results indicate the more recent models, that compute a mass balance of NH3 from excretion to landspreading, have tended to focus uncertainty onto the dietary efficiency of animal N nutrition. After excretion, the total ammoniacal nitrogen (TAN) in the manure contributes to NH3 emissions at each stage as the manure passes from the animal housing to storage and to landspreading. There are many variants of these processes because every farm is different, resulting in diminished sensitivity to any one NH3-loss mechanism after excretion. This finding suggests that although NH3-emission factors, the empirical data at the core of the models, are not well characterised (especially for Canadian conditions), it is at least as important to expend research effort on factors that influence TAN excretion. Results of this paper will also guide development of the NAHARP/NAESI model. Key words: NAHARP, livestock, manure, Fraser Valley, ammonium sulphate, PM2.5
Print ISSN:
0008-4271
Electronic ISSN:
1918-1841
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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