with this option. as Direct inhalation of too high ozone {if you smell it} actually burns your alveoli - by corollary I once killed all the plants in a nursery in 10 minutes by having the ozonator ON THE INLET to the nursery - they literally looked burnt. There is actually a medical condition caused by breathing too much ozone - essentially a type of Asthma.
The Ioniser is the safer option in a room environment.