Ozone produced by corona discharge in the presence of water

Significant levels of ozone have been detected in a reaction flask that was designed for studies using negative air ions generated from corona discharge. While diluting the gas in the vessel at the rate of 1.5 liters/min., more than 1.0 ppm O₃ was measured in the vessel when grounded water was present. Ozone levels were much less (15 ppb) in ambient air near the ion generator. Even in the absence of water, O₃ levels were only 7 ppb in the reaction flask. Without the corona discharge apparatus, levels of ozone in the gas phase (with water present) averaged 6 ppb. These results demonstrate that when negative air ions are generated from corona discharge in the presence of water, significant levels of ozone are produced. Therefore, O₃ could be directly responsible for many of the oxidizing effects that have been reportedly due to negative air ions.