A series of sensitivity tests were run for the Meteorological Service of Canada to determine the optimum parameterization of a continental-scale dry deposition model for airborne acidic species (HNO3, SO4=). The work included: model development, analysis of ground vegetation factors affecting the surface uptake of these species, development of standard databases of input parameters for the model applicable to North America, measurement of vegetation parameters at selected sites in eastern Canada, model sensitivity analysis to vegetation factors and recommendations for vegetation factor data measurement and database development.