Abstract: An aerosol inhalation device assembly for diagnostic and therapeutic use for deep lung alveolar aerosol targeted drug delivery includes a nebulizer for generating an aerosol containing droplets of a liquid. The nebulizer has a pressurized gas inlet and a nebulizer outlet. An inhalation chamber is in fluid communication with the nebulizer outlet. The inhalation chamber is defined by at least one sidewall. An inhalation mouthpiece assembly is in fluid communication with the inhalation chamber and extends outwardly from the at least one sidewall of the inhalation chamber. A filter assembly is in fluid communication with the inhalation chamber. The filter assembly includes a filter medium. An exit port is in direct fluid communication with the filter assembly. A method of using the nebulizer is also provided.