NOVELTY - A multi-electrode system for decontaminating a gas containing contaminants, comprises a passageway for allowing the gas to flow from a first end to a second end of the passageway; set(s) of three electrodes having two outer electrodes forming a first terminal and one inner electrode forming a second terminal; and a high voltage waveform source for creating electrical fields between the outer electrodes and the inner electrode.    USE - The inventive system is used for decontaminating a gas containing contaminants, e.g. at least one of airborne pathogenic agents, microorganisms and undesirable chemical substances. It can be used in critical applications, e.g. sterilizing or decontaminating hospital rooms, and sterilizing or decontaminating the outside air used by military personnel in shelters or vehicles.    ADVANTAGE - The inventive system is effective in decontaminating gases containing contaminants.    DETAILED DESCRIPTION - A multi-electrode system for decontaminating a gas containing contaminants, comprises a passageway for allowing the gas to flow from a first end to a second end of the passageway; set(s) of three electrodes having two outer electrodes electrically connected together forming a first terminal and one inner electrode placed between the two outer electrodes and forming a second terminal, where each set is placed within the passageway and in one of a perpendicular and a parallel orientation to the gas flow; and a high voltage waveform source for supplying the first and second terminals and creating electrical fields between the outer electrodes and the inner electrode. The electrical fields interact with the gas to create an electronic current having a desired average energy level to at least match the energy level of the molecular bonds of the contaminants to be at least one of ruptured, damaged and modified. The set has at least one of surface(s) of the inner electrode and a corresponding exposed surface of the outer electrode, and a space between the outer electrode and the inner electrode. The surface of the inner electrode and the corresponding exposed surface of the outer electrodes are fitted with protuberances having a controlled geometry on the surface, thus controlling amplification factor of the electric field at extremities of the protuberances. The space between the outer and inner electrodes is least partially filled with elements made from a dielectric material.    DESCRIPTION OF DRAWING(S) - The figure is a schematic view of a system diagram including four basic processing stages.    Electrodes (4-6, 9-11, 15-17)    Controller (7)    Impedance network (8, 13, 18)    Peaks (14)    Electrically grounded (19)    Warning (25a-25c)