Ozone, (O3), sometimes is called "activated oxygen". Ozone contains three atoms of Oxygen rather than the two atoms which we normally breathe. Ozone is the second most powerful sanitizers in the world and can be used to destroy bacteria, viruses and odors. Ozone occurs naturally in nature, most often as a result of when lightning strikes which occur during thunderstorms. The "fresh, clean, spring rain" smell that you notice after a storm most often results from nature’s creation of ozone.