In this day and age, aerosol therapy is very often the method of choice.

The debate as to whether inhalation works on the entire system or only on the mucous membrane was settled in the nineteenth century. The lungs occupy a large area through which substances that are inhaled are absorbed in a very brief time. The expected action is remarkably rapid, comparable to that of intravenous injections. Administering aerosols by way of inhalation is closely bound up with questions relating to the quantity of mist, its contents, density and dosage, as well as the degree and scale of its dispersal.

Those parameters, as well as the aerosol’s electrical properties, its gravitation and the speed at which the inspired air stream flows are not only crucial to the mist’s ability to penetrate the respiratory tract. Its optimal settling and absorption into the mucous membranes also depends on those factors. Mists which are very finely dissipated and are thus widely and uniformly dispersed settle in the deepest-lying sections of the respiratory tract, where more than fifty per cent of the original amount undergoes absorption.

When a dispersion characterised by the occurrence of large droplets is used, only a negligible part of the mist generated will be absorbed. The particle size best suited to absorption into the mucous membranes of the respiratory tract ranges from 1.8 to 5 µ. Halogenerators make the micronisation of salt possible, producing very fine particles of salt aerosol which make their way to the deepest parts of the lungs. In order to ensure the therapeutic efficacy of the mist generated, it is essential to take a diverse range of factors into consideration and select the treatment parameters accordingly.

Development in matters relating to therapeutic aerosol generation is dependent on a number of factors. One of the most crucial is technological progress in the design and construction of the generating equipment.