A diagnostic analyses is presented to assess the impact of non-precipitating clouds on rates of change of pollutant concentration both in the mixed layer and in the free troposphere. This analyses is based on a coupled two layer (mixed and free tropospheric) conservation of pollutant species model which distinguishes the role of active or venting type clouds from the forced, or fair weather cumulus clouds. The study examines the sensitivity of the modeled rates of change of pollutant predictions in the mixed layer and in the free troposphere to the method by which the vertical exchange of these venting class clouds is modeled. This analyses focus on the vertical redistribution process, the heterogeneous conversion process which are known to be rapid and important is ignored in the study by considering only total pollutant concentration.