Atmospheric dispersion modelling is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. We use specialist computer programs to solve the mathematical equations and algorithms which simulate the pollutant dispersion. The dispersion models are used to estimate the downwind ambient concentration of air pollutants or toxins emitted from sources such as industrial plants, and offshore installations. Models can also be used to predict future concentrations under specific scenarios (i.e. changes in emission sources). As part of a PPC application process, you may be asked to include an Air Dispersion Modelling report within your application.