What is depleting the ozone layer?
There are a number of compounds that have led to an increase in the amount of chlorine and bromine in the atmosphere: Chlorofluorocarbons (CFCs) do not exist naturally, but are man-made compounds containing chlorine, fluorine and carbon. Production of CFCs began in the 1930s when they were first used in fridges. After the Second World War however, the amount of CFCs being produced increased as they were also used in aerosols, air conditioning units and for various other purposes. When CFCs were first developed they were thought of as safe, inert gases with numerous uses and believed to cause minimal environmental damage. CFCs, when released from the surface of the Earth, rise slowly into the stratosphere. Once there, they are bombarded by the incoming UV light from the Sun, releasing the chlorine atoms from the parent compound, which can then react with the ozone molecules (Figure 3). Eventually the chlorine atom is removed from the atmosphere by other reactions.
