It is a colourless and odourless gas. Ozone One of the several gases that make up the Earth's atmosphere. If all the ozone contained in the atmosphere from the ground level up to a height of 60 km could be assembled at the earth's surface, it would comprise a layer of gas only about 3 millimeters thick, and weigh some 3000 million tones.
Ozone is toxic at high concentrations because it reacts strongly with other molecules.
Each ozone molecule is made up of three oxygen atoms. Users of these web pages are deemed to have read and accepted the conditions described in the Copyright Notice and Disclaimer .