A New Trajectory Model and Its Practical Application for Accident and Risk Assessments

Since the conventional straight-line Gaussian diffusion model is only applicable to environmental exposure calculations under constant meteorological diffusion conditions and as the so-called advanced diffusion models are, as a rule,not suited because they are not (or insufficiently) calibrated and validatedthe required input parameters such as vertical wind and temperature profiles are difficult to obtaina classification according to diffusion categories is problematicthe diffusion and weather march statistics required for important ranges of application are lackingthe evaluation requires a sophisticated numerical integration, we have extended the Gaussian diffusion model to cover non-stationary diffusion conditions in a so-called volume source model, which permits calculation of the environmental exposure due to released pollutant puffs taking account of the change in wind velocity, wind direction, diffusion category and precipitation intensity during transport, using customary diffusion parameters and the diffusion as well as weather march statistics available for many sites.