What is Damaging the Ozone Layer
In the 1970s, American researchers discovered that a variety of man-made chemicals were causing ozone depletion.
These included chlorofluorocarbons – or CFCs for short – which were invented by Thomas Midgley in the 1930s.
At the time, Midgley was highly regarded but unfortunately, time has altered the way he will be remembered in history. (He was also responsible for leaded fuel – which has increased our carbon burden.)
Wonder chemicals?CFCs had a huge range of applications in industry and were at first regarded as wonder chemicals because they were inexpensive, non-flammable and thought to be totally non-toxic.
In the 1930s, they were used in refrigeration and over the years, their use became widespread in air conditioning and eventually, in aerosol cans – providing the propellant needed to spray everything from hairspray and air-fresheners to paint and solvents. For some time, they were also used in asthma inhalers.
Ozone Depleting SubstancesCFCs, which contain carbon, chloride and fluorine are now known to damage the Ozone Layer but there are a number of other industrial processes and man-made chemicals which also cause damage.
CFCs are probably the best known member of a group of chemicals, known as halocarbons which are regarded as Ozone Depleting Substances. Another culprit is halogen gas which contains bromine and is thought to be even more damaging to ozone than CFCs. This has been used in everything from fire extinguishers to computers and aeroplane engines.
Halogen source gases are not reactive at ground level and some dissipate or are absorbed by seas but those that are carried upwards become reactive due to radiation from the sun and then become capable of damaging ozone – and ultimately, our environment.
Unfortunately, halons are not easily dissipated by rain or snow and they can exist for many years in the atmosphere. To get an idea of the damage they can cause, experts believe that just one atom of carbon in the stratosphere can destroy up to 100,000 ozone molecules.
Banning of CFCsSweden was the first country to outlaw the use of CFCs in aerosol sprays and other countries soon followed suit. However, it was still used in some other products and industrial processes and CFC production in the UK did not finally come to an end until 2000.
Scientists now expect that bromine levels will peak before 2010 and then begin to drop but since a high proportion come from uncontrolled or natural sources, such as the sea, it will take many years for levels to drop significantly.
At the moment, hydrochlorofluorocarbons (HCFCs), which are somewhat less damaging, are being widely used in place of CFCs but global reduction targets have now been set for these and HCFCs will be banned in the European Union from 2015.
Unfortunately, there is growing evidence that equipment and products outlawed in many other countries because of their CFC content are being illegally exported to Third World Countries by unscrupulous operators.
On International Ozone Day 2008, for example, government officials in Indonesia admitted that illegal importation of products containing Ozone Depleting Substances – such as banned refrigerant for air conditioning - was still widespread.