Fig. 1

Schematic representation of the exposure system developed by Marjanovič and Kotnik [19]. The system is enclosed by a transparent plexi-glass tube (a). An internal container also made of plexi glass (b) prevents the electric arc from short-circuiting the conical emitting electrode (c) and the ring-shaped receiving electrode (d). The emitting electrode is in the air above the sample, while the receiving electrode is in direct contact with the outer edge of the disk-shaped sample. An electric arc is illustrated (e) as exiting downwards from the emitting electrode into the sample containing the spores (f) deposited on the Petri dish (g)