It is concentrated in a layer between 7 and 22 miles above the earth's surface. The massive depth of the ozone in the stratosphere would lead you to believe that it is very thick, it is not. If it were condensed, the ozone layer would only be a few millimeters thick Rowland and Molina 1994. p.23).
The ozone is made in the stratosphere. It is continuously being formed, broken down, and reformed, over and over again. Furthermore, the three key elements of the cycle are: oxygen, ozone, and the energy from the sun. The ultimate source of energy for our planet is the sun. This energy travels through space in the form of electromagnetic Radiation. Furthermore, this electromagnetic radiation is often referred to as waves and their length, therefore, wavelengths. The sun has a wide range of wavelengths. This range is known as the Electromagnetic Spectrum. In this spectrum there is Gamma, Ultraviolet, Visible, Infrared, and Radio waves.
It is the ultraviolet (UV) radiation coming from the sun that drives the ozone cycle in the stratosphere. When an oxygen molecule is hit by a high-energy UV ray, the O2 molecule absorbs the ray's energy. As a result, the bond holding the oxygen molecule together breaks apart. These separate molecules quickly join with nearby oxygen molecules to form an ozone molecule. At this time, the entire process repeats itself making new molecules that are separated which combine to make new molecules, over and again (Rowland and Molin 1991 p. 42).
As a result of this cycle, about the same amount of ozone is produced as is broken down in the stratosphere. Therefore, the amount of ozone stays the same under normal circumstances (Rowland and Molina 1991 p.43). A constant and stable ozone layer is important for life on earth because the high-energy UV rays that are absorbed in the ozone layer are extremely dangerous. These rays can kill some things while seriously damaging others.
