The development of transgenic crops has created concern regarding cross pollination from transgenic crops to conventional crops or wild relatives.  In response to these concerns, studies involving the dispersal and deposition of pollen have striven to predict the amount of pollen that is transported to plants in other fields.  Even if pollen transport is accurately predicted, it is essential to determine whether the pollen is viable when it reaches a receptor. We have developed a simulation model which predicts changes in the viability of  pollen as it transported through the atmosphere.  Through the use of a Large-Eddy Simulation (LES) model and a Lagrangian particle dispersal model, the factors affecting viability of individual particles can be examined along the particle trajectory and the resultant viability of individual particles determined.  The LES model predicts fields of winds, temperature, and specific humidity to drive the dispersion model, which will predict the pollen trajectories and viability.  By predicting the pollen lifespan through numerical models and determining whether pollen stays viable over long distances, the actual potential for cross-pollination can be more closely examined.