Sentry and Nocturne models use 254nm wavelength UV-C which does not produce ozone, and we have tested our units to ensure that it is ozone free. However, XN model uses 185 nm wavelength UV which reacts with oxygen (O2) to form ozone (O3) and is specially designed to produce ozone.In fact, nature ozone is produced by UV from the Sun and from lightning. This is why after thunderstorms the thin layer of ozone will make the air feel fresh. However, excessive concentration of ozone can be harmful to people.Some inferior UV products may generate ozone because the wavelength of UV light it produces is unstable, and this is why OXIRA chooses to use the top quality German UV tube to give our customers the best protection.
