The objective of this article is to investigate some of the classical parameterizations used for modeling mass transfer between interstitial gas and cloud droplets for aqueous phase models in Air Pollution Modeling (\cite{schwartz}). After an appropriate scaling of the initial model (a set of two coupled Partial Differential Equations) we apply some theoretical results of Reaction-Diffusion models with large diffusion coefficients. One of the key results is the importance of the liquid water content as compared to the ratio of diffusion timescales to chemical timescales. We propose moreover a new parameterization of mass transfer taking into account aqueous-phase diffusion limitations.