Abstract: An apparatus for producing ozone, comprising: a first electrode; a second, annular electrode surrounding the first electrode and spaced therefrom; a first tubular wall of electrically insulating material disposed between the electrodes; a first sealed glow discharge chamber surrounding one of the electrodes, formed at least in part by the tubular wall, and filled with a charge of an ionizable gas; an ozonization chamber disposed between the electrodes, formed at least in part by the tubular wall, and having an inlet for an oxygen charged medium and an outlet for the medium as ozone enriched; and, electrical conductors for connecting the electrodes to an electrical power source, whereby ionized gas in the glow discharge chamber forms a plasma electrode. The apparatus is preferably energized by applying an electrical potential between the electrodes in the form of voltage pulses at a frequency in the range of 10 to 60 KHz.