[Local weather-condition and behaviour of anthropogenous aerosols : two examples (author's transl)].

It is today accepted that the developing and propagating of epidemic diseases of the airways are sometimes related to some weather conditions and that, in this context, the complex aerosols such as fogs and smogs can play an important part in carrying viruses and bacteria. This communication intends to demonstrate two examples of how weather conditions can and must help to interprete the observations and measurements done on particles of atmospheric aerosols which are more or less derived from human activity. One of the examples is related to the study of variations of numerical concentrations of particles in an atmosphere under-saturated with respect to water. The other example is related to the development and extension of a phenomenon favouring the fog formation from a localized industrial source.