A brief review is made of data bases which have been used for developing diffusion parameterizations for the convective boundary layer (CBL). A variety of parameterizations for lateral and vertical dispersion, (sigma sub) and (sigma sub z), are surveyed; some of these include mechanical turbulence, source height, or buoyancy effects. Recommendations are made for choosing among these alternatives, depending on the type of source. Because observations of passive plumes indicate that the Gaussian model does a poor job of describing vertical diffusion in the CBL, alternative models for predicting dimensionless crosswind integrated ground concentration, are reviewed and compared.