As soon as ozone is created in ozonator and dispersed in a room, it will start to revert back to oxygen.
This process occurs by several phases including the following: oxidation reactions with an organic material such as odors or smoke, reactions with bacterias, viruses, molds etc., which again consumes ozone by oxidation reactions. Due to the fact that ozone reacts with these and many other compounds, the ozone concentration decreases rapidly. Additionally ozone breaks down thermally, that is higher temperatures destroy ozone quicker than lower temperatures.
When most of the compounds are already oxidized, is formed a ozone residue whose concentration is not falling quite as quickly. This ozone residue degrades to oxygen in accordance with a half-life of ozone for the environment in which it has been applied. Typical half-life decay times can be checked in the tables given in the article on ozone properties.
So ozone, despite its strength, is not being too long in the air . Fulfills its role, and then disappear changing themselves back into safe oxygen.