Depletion of the Ozone Layer
The ozone layer is a part of the earth's stratosphere which absorbs the majority of the radiation emitted by the sun. This protective layer consists of Ozone which absorbs the majority of the ultraviolet B radiation which is responsible for sun tans but also skin cancer and sun burns therefore it is important that the ozone layer is protected. The ozone layer is situated about 15 to 30km above the earth's surface.
This depletion of the ozone layer begun in about 1984 when CFC's (chlorofluorocarbons) were started to be used widely all around the world, mainly in refrigerators and Aerosols. These substances are extremely un-reactive which allows them to reach the ozone layer without reacting with anything on their way. When they reach the ozone layer they are broken down by the UV rays which give them enough energy to break their bonds. Then these CFC's react with Ozone which is an extremely reactive molecule. These CFC take about 5 years to reach the stratosphere and can stay there for 2 to 3 years; 1 molecule of CFC's can destroy up to 100 000 molecules of ozone
As you can see in the picture below, this is the chemical reaction which takes place when chlorine reacts with ozone. After reacting, the chlorine breaks down the ozone molecule into an oxygen molecule and a molecule of chlorine oxide. After that, the chlorine oxide molecule reacts with ozone to make 2 oxygen molecules and a chlorine molecule. This makes the process continue for a very long time which destroys the ozone layer, enabling more UV Radiation to go through.
The Solution?
The Solution to solve this issue is the ban of these chemicals. Since 1996, Chlorofluorocarbons have been banned in the USA and other chemicals have been used to replace them. Although the majority of the developed countries no longer uses Chlorofluorocarbons, there are still some under-developped countries in Asia which use these chemicals since they are cheap and compatible with older devices. If we were to educate the people in these countries and if the countries themselves were to ban the use of these chemicals, this problem would be solved.