A simple diagnostic model of cumulus convective clouds is developed and used in a sensitivity study to examine the extent to which the rate of change of mixed and cloud layer pollutant concentration is influenced by vertical transport and chemical transformation processes occurring as a result of cumulus clouds. The aqueous phase chemical transformation process is parameterized and modeled as a flow through batch reactor. The net vertical exchange between the mixed and cloud layers by cumulus cloud elements that protrude above the dry convective mixed layer is modeled as the product of a venting velocity and the difference in pollutant concentration between the mixed and cloud layer. The two layer model yields an analytic expression involving key parameters such as areal extent of cloud cover, dry deposition rates, thickness in mixed and cloud layers, and the initial concentration difference between the mixed and cloud layers. The model solution was programmed using LOTUS 123.