The invention relates to a control device (10) for a medical aerosol delivery device (2), a medical aerosol delivery system (1), a method for controlling a medical aerosol delivery device (2), a computer program element for controlling such device or system, and a computer readable medium having stored such computer program element. The control device (10) for a medical aerosol delivery device (2) comprises a provision unit (11), a processing unit (12), and a control unit (13). The provision unit (11) is configured to provide inhalation length data per breath. The processing unit (12) is configured to compare the provided inhalation length data with a predetermined inhalation length threshold, and to filter provided inhalation length data below the predetermined inhalation length threshold. The control unit (13) is configured to control the medical aerosol delivery device (2) based on the filtered inhalation length data.