2. Objectives and principles of atmospheric dispersion modeling

2.1 Objectives

The aim of atmospheric dispersion modelling is to know the concentrations of species released at any point in space and at any time. At this level, we need to distinguish between two types of atmospheric release:

• that which follows an incident or accident (e.g. release of a puff of pollutant);

• and that resulting from the normal operation of a plant ("routine" discharge linked to the plant process).

In modeling, these two situations are treated in different ways, since they do not call on the same types of data, particularly meteorological data. Routine releases are modeled on the basis of meteorological statistics, whereas accidental releases are modeled...