This aerosol generation system enables the production of monodisperse metal oxide aerosols which can be labeled radioactively. The production method consists of the nebulization of a metal-salt solution into monodisperse droplets by a 'May spinning-top aerosol generator', predrying of the droplets, crystal water extraction out of the salt crystals, thermal degradation up to 1200 degree C into metal oxide particles and subsequent cooling to room temperature. Cobalt oxide aerosols with **5**7Co radioactive labeling have been produced and analyzed extensively. In order to study the influence of the angular air jet on the efficiency, measurements have been carried out in which the ratio of the mass of monodisperse droplets per unit time and liquid feed rate is calculated. The size of the droplets follows the equation of Walton and Prewett. In order to study the stability of the aerosol particles, a standardized long-term dissolution test has been developed.