Potential for mitigating atmospheric ammonia in Canada

Abstract

Most ammonia (NH 3 ) emissions (85%) in Canada come from agricultural sources (400 kt/yr). There are international conventions that require countries to mitigate NH 3 emissions but there are no federal or provincial guidelines in Canada stipulating emission targets or best practices for agriculture. This study examines the potential for mitigating atmospheric NH 3 using a range of approaches. Taking current farm practices into account, employing proven low-cost measures (low-emission slurry application and slurry storage covers) would reduce annual emissions from livestock operations by 16 kt NH 3 -N, while using all available low-cost measures would reduce emissions by 79 kt NH 3 -N or 26% of livestock emissions. Another 36 kt/yr could be avoided by improving fertilizer practices, so that the total potential reduction would be about 29% of all agricultural emissions. Emissions from beef cattle and pig production could be reduced by 18% if consumption was cut by 50%, with greater mitigation if production for export was reduced, although the economic and social consequences need to be considered. Mitigation practices must be viewed in the context of possible pollution swapping especially in surplus nitrogen situations. Emissions must also be considered in terms of atmospheric NH 3 transport to and from the USA, therefore bi-national agreements to jointly reduce emissions might be needed. It may be more cost-effective in Canada to strategically reduce emissions to minimize risks to health (from particulate matter) and the environment rather than to reduce annual national emission targets.

Ambient Ammonia Concentrations Across New York State

“…NH 3 has other potential adverse environmental effects. For example, long-range transported NH 3 can reduce the biodiversity of remote ecosystems (Bittman et al, 2017;Ellis et al, 2013). Deposited NH 3 and ammonium (NH 4 + ) formed by reacting with acid gases in the atmosphere can cause aquatic eutrophication (Tang et al, 2017).…”

“…Although there have been efforts to reduce agricultural NH 3 emissions at local to international scales (Bittman et al, 2017;Tang et al, 2017;Wang et al, 2017), Bittman et al (2017) suggested that atmospheric NH 3 concentrations are not declining in Canada and the United States because the reductions in acid gas concentrations tend to increase its residence time and resulting NH 3 concentrations (Meng et al, 2017;Pinder et al, 2011).…”

Effect of changes in management practices and animal performance on ammonia emissions from Canadian beef production in 1981 as compared with 2011

“…Manure N in excess of that required for crop production was assumed to have been spread on tame and (or) seeded pastureland. Based on Bittman et al (2017), 57% of solid manure from Canadian beef farms was assumed to be spread on tilled land. In Canada, stockpiled manure is typically land spread in the spring or fall (Sheppard and Bittman 2012;Sheppard et al 2015).…”

“…In contrast, NH 3 -N emissions from grazing cattle occur primarily from urine patches deposited on pasture (Sheppard and Bittman 2016). These deposits have a small surface area and much of the urine infiltrates into the soil (Bittman et al 2017). As a result, NH 3 emissions associated with confined cattle are normally greater than those that are grazing.…”

Nitrogen Recovery and Loss from Kentucky Bluegrass Fertilized by Conventional or Enhanced-Efficiency Urea Granules

“…Ammonia deposition to surfaces, the primary atmospheric removal mechanism, is considered a significant threat to terrestrial and aquatic ecosystem health [5,6]. The majority of atmospheric ammonia in the US and Canada originates from livestock operations and fertilizer application [7,8].…”