The traditional way of producing ozone is by means of Dielectric Barrier Discharge or so-called Silent Electrical Discharge. Typically, dry feedgas - either air or oxygen - is passed through a gap formed by a high voltage electrode and an earth electrode. When high voltage at high frequency is applied to the high voltage electrode ozone is produced in the feedgas by the micro-discharges taking place in the gap. The geometry of the gap and the quality of the dielectric material are of paramount importance and are normally closely guarded secrets by the ozone generator manufacturer. The make-up of the feedgas is, however, equally important and has become a much-debated topic.