The arrangement for introducing a desired quantity of decontamination agent into an enclosure (9) comprises in the first instance a tank (T) as a storage vessel for making available the decontamination agent in liquid form. The main constituent part is a dosing device (1) with a spray nozzle (18) directed into the enclosure (9) for the purpose of atomizing the decontamination agent. At least one feed line from the ambient air (U), a compressed air connector (+P) and a controller (8) are provided for operating the dosing device (1). The dosing device (1) has a dosing vessel (2), which has a storage space (20) of defined volume for receiving an individual portion of decontamination agent. The storage space (20) is intended to be filled cyclically with a number (n) of portions of decontamination agent from the tank (T), and the portion contained in each case in the storage space (20) is introduced through the spray nozzle (18) into the enclosure (9) before a subsequent portion is received. The portion number (n) for achieving the desired quantity of required decontamination agent can be chosen between 1 and a whole multiple of 1. The storage space (20) is configured with a fixed or adjustable size and is formed as a separate container, cylinder, recess in the dosing vessel (2) or as an extended or looped tube length. The storage space (20) preferably has a volume in the range of 1 cm3 to 5 cm3.
