The third oxygen atom of ozone makes it very active. This atom is easily attached to other odor molecules. When pollutants such as odor, bacteria or viruses come into contact with ozone, their chemical structure will change into compounds with low odor. As more ozone attacks the remaining compounds, the odor is eventually destroyed. This process is called oxidation. Ozone is basically restored to oxygen after use. This makes it a very environmentally friendly oxidant.