2. Dispersion-related physical mechanisms

The term "atmospheric dispersion" characterizes the fate, in time and space, of a pollutant or group of pollutants (aerosols, gases, dust, odors, etc.) emitted into the atmosphere under given conditions. Atmospheric dispersion modeling must establish a relationship between emission (the source) and immission (the target), under the influence of various physical parameters.

Turbulence and atmospheric stability are two fundamental physical parameters involved in the transport and diffusion of pollutants.

• Transport is the average movement of gaseous particles under the combined effect of wind and the specific characteristics of the pollutants emitted (speed, temperature, density).

• Diffusion is the relative displacement of gaseous particles with respect to their...