Quantifying atmospheric deposition of critical pollutants is important in assessing their life time in air and their potential impact on various ecosystems.  Recent progresses in Environment Canada on the development of numerical algorithms and frameworks for the estimation of atmospheric deposition of different groups of air pollutants will be discussed.  These developments include (1) a new dry deposition algorithm for bulk fine, coarse and giant aerosol particles; (2) a new semi-empirical algorithm for below-cloud scavenging by rain and snow for size-resolved aerosol particles and a further extended algorithm for bulk fine, coarse and giant particles; (3) a modified atmospheric gradient method quantifying dry deposition fluxes of ozone and acidifying pollutants over forest canopies; (4) a bi-directional air-surface flux exchange scheme for elemental gaseous mercury; and (5) a framework mapping atmospheric deposition of polycyclic aromatic compounds in the Athabasca oil sands region.