[Physical basis and therapeutic range of application of ultrasonic aerosols (author's transl)]

An aerosol of an aqueous solution still changes its size from development up to alveoli; therefore only conclusions can be made about possible sizes of particle spectrum. Volatilisation, condensation, coagulation and sedimentation are the important interfering factors. To characterize an aerosol one should know the aerosolvolume, the quantity of nebulised substance and the relative size distribution. A method for measurement of size distribution -- a radioactive aerosol was deposited in a spiral centrifuge -- is described and the aerosol of two ultrasonic nebulizers were compared. Because of their physical properties aerosols of ultrasonic nebulizers play a main part in prophylaxis and therapy of functional lesion of bronchopulmonary affections.