Application Note MOISTURE METERS Ozone (O3) is a powerful oxidising agent widely used in water treatment, wastewater sterilisation, food/pharma feedwater treatment, swimming pool disinfection and other industrial processes. Compared to chlorine, ozone offers advantages such as higher oxidation potential, no harmful chlorinated by-products and environmentally benign oxygen residuals. Ozone generation, especially via corona discharge (CD), is extremely sensitive to moisture in the feed gas. Even small increases in water vapour can reduce ozone yield, cause arcing, increase nitric acid formation, accelerate corrosion and drastically decrease the life and efficiency of ozone generators. Moisture measurement, therefore, is not optional; it is a critical control parameter. The two main industrial ozone generation methods: • Corona discharge (CD) is the most common; uses high-voltage electrical discharge to split O2, allowing recombination into O3 • UV light is used only for small-scale applications and produces a lower yield • Oxygen Intake: The generator draws in oxygen from the surrounding air or a concentrated source • Energy Application: A high-voltage electrical current (corona discharge) or ultraviolet (UV) light is applied to the oxygen. • Molecular Splitting: This energy breaks apart the stable O2 molecules into highly reactive, individual oxygen atoms (O). • Ozone Formation: These unstable single atoms quickly bond with other intact O2 molecules, creating ozone (Os). • Oxidation: The generated ozone reacts with contaminants such as odour molecules, bacteria and viruses transferring an oxygen atom which disrupts their molecular structure, breaking them down and neutralising them. • Reversion: Ozone is unstable and eventually reverts to regular oxygen (O2) after it has reacted. • Potable water production • Food and pharmaceutical water sterilisation • Swimming pool water treatment • Wastewater sterilisation before environmental discharge These applications rely on consistent, high-yield ozone production, which is directly impacted by dew point.

Arcing and electrical failure Corona discharge ozone generators rely on a stable high-voltage electrical field. When moisture enters the feed gas (air or oxygen), it increases the gas's electrical conductivity, leading to: • Arcing between electrodes • Electrical breakdown across the dielectric • Physical damage to the electrodes and chamber walls • Premature generator failure Formation of nitric acid and corrosion If moisture is present, the corona discharge converts nitrogen (from air or non pure oxygen) into nitrogen oxides. These combine with water vapour to form nitric acid inside the generator....