What are ozone and the ozone layer?
Ozone (O3) is a molecule made up of three oxygen atoms. The oxygen we breathe (O2) is similar but has only two oxygen atoms. High up in a region of the upper atmosphere known as the stratosphere, light rays can break down breathable oxygen into two individual oxygen atoms. Single oxygen atoms are quite reactive, and ozone is formed when one of these lone oxygens bump into and combine with O2. But ozone isn’t very stable either. If a high-energy light ray, in particular ultraviolet-B (UV-B), strikes an ozone molecule, it too will break down, back to the lone oxygen and O2. Other molecules naturally found in the stratosphere, such as nitrous oxide, can also react with O3 and break it down. Over time, as the atmosphere formed, the reactions that create and break down ozone came into a dynamic equilibrium. The result was a small residual amount of ozone concentrated in a band between nine and twenty-two miles high in the stratosphere. This is the band popularly referred to as the ozone lay
Ozone (O3)–a molecule made up of three oxygen atoms. In the stratosphere, sunlight breaks down oxygen into two individual oxygen atoms. Ozone is formed when one of these lone oxygens combines with O2. Over time the reactions that create and break down ozone came into a dynamic equilibrium. Result–the ozone layer–a small residual amount of ozone concentrated in a band high in the stratosphere. This equilibrium is delicate: For every ten million molecules of air, two million are O2, and only three are ozone. This small amount of ozone is enough to prevent most UV-B radiation from reaching the surface of the earth. What have humans done to the ozone layer? Damaged the ozone layer by adding molecules containing chlorine or bromine that lead to ozone destruction. Chlorofluorocarbons (CFCs)–at ground level, these molecules are stable and have uses in industrial and domestic applications. However, when they are released into the atmosphere, they drift up to the stratosphere, pushed by win
