2. Objectives and principles of atmospheric dispersion modeling

2.1 Objectives

The aim of atmospheric dispersion modelling is to determine the concentrations of released substances at any point in space and at any time (spatiotemporal approach). At this level, we need to distinguish between two types of atmospheric release:

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

• and that resulting from the normal operation of a plant ("routine" discharge, continuous or repeated, linked to the plant's process).

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