Schematic overview of the aerosol collection device (ACD). (a) The device consists of an acrylic glass chamber of 27 l, including a HEPA filter to remove particles from incoming air. The ACD is connected to nebulizers, which use either jets or ultrawaves to generate aerosols. The air containing these aerosols is actively pumped through the multi-stage impinger. The airflow is measured by a flowmetre. The HEPA filter in front of the pump and flowmetre protects the equipment. (b) A photograph of level 1 of the impinger equipped with three different surfaces to collect settling aerosols, i.e., (I) glass coverslip for viability testing as appraised with CFU and live/dead microscopy staining, (II) copper grid for EM analysis, and (III) mica for atomic force microscopy analysis.