An analysis of the impact of the Sudbury smelters on wet and dry deposition in OntariO

Meteorological analyses of acidic deposition data were undertaken to quantify the effect of Sudbury emissions on precipitation quality and air quality in Ontario during the period 1980–1983 with particular emphasis on the Sudbury smelter shutdown period (July 1982–March 1983). The techniques used included air parcel trajectories and detailed meteorological analysis.Results indicate that the contribution of the Sudbury smelters to sulphate wet deposition in central and southern Ontario was small—less than 12 % of the wet deposition at the study sites. The smelter contribution to sulphur dry deposition was greater—possibly as high as 47 % of the total at Kapuskasing, and up to about 20–30% of the total in central Ontario, with a smaller contribution (less than 5 %) to the southwest and west of Sudbury. These percentages apply to the smelter emission rate in the early 1980s, i.e. about 0.9 million metric tons of SO₂ per year.