(A) Sketch of the device used for the aerosol spray deposition of B. subtilis 168 spores. The spraying device consists of the following components: 1, N2 supply; 2, power-driven 3/2 magnetic valve; 3, two-substance nozzle with solenoid valve and power connector; 4, microprocessor-based quartz counter. (B) Computer-aided-design (CAD) drawing of a two-substance nozzle (provided by Schlick, Untersiemau, Germany) with the following components: 1, inlet of liquid sample; 2, inlet of pressurized N2; 3, variable nozzle air cap for controlling the spray radius. (C) Circuit sketch of the electrical wiring connecting the microprocessor-based quartz counter with the magnetic valve and two-component nozzle for the synchronized opening of the N2 inlet and liquid inlet, respectively. The power button was added between port 1 and port 2. A voltage of 230 V at 50 Hz was applied to ports 9 and 10. Ports 8 and 10 are interconnected.