Observations of annual wet deposition of sulfur made during 1980 at 62 stations in northeastern America are interpreted using a statistical long-range transport model. This work is meant to demonstrate the role of an empirical model in the analysis of observations. Our analysis points to the following conclusions: 1. (1) The parameters that represent the conversion of SO 2 to SO 4 and the wet and dry removal of sulfur are insensitive to concentration levels, 2. (2) the variation of the wet deposition field is closely related to the distribution of sulfur emissions and 3. (3) observations demand efficient wet scavenging of SO 2.