In order to assess the environmental impact of toxic chemicals in the United States, the Oak Ridge National Laboratory (ORNL) is developing a multimedia model to estimate the transport, diffusion, and removal of chemicals in the air-water-soil system. The Atmospheric Turbulence and Diffusion Laboratory (ATDL) was charged with assisting ORNL in the further refinement of the air transport and diffusion model and providing guidance on removal processes for toxic chemicals. This report is a review of the findings on removal processes. An overview is given of the general formulas and experiments regarding removal processes. Sections 3 and 4 contain specific removal methods for trace organic chemicals. Section 5 contains an application of the box model to simply account for all removal mechanisms discussed here. It soon became evident that there is disagreement among the experts regarding the quantitative estimation of removal of common pollutants, and nearly complete ignorance regarding specific organic chemicals.