1. FIXING THE OZONE HOLE Discuss the problems associated with the use of CFCs.

2. CFCs(Chlorofluorocarbons) have many industrial and domestic applications, they are widely used in refrigerators, fire extinguishers, blowing plastic foams etc… Fire Extinguishers Refrigeration and air-conditioning Aerosol cans They are used widely because they are very stable compounds containing only C, F and Cl and they last for a very long time. CFCs were such an excellent discovery as scientists have been searching for a similar and very stable chemical. The overuse of CFCs however led to huge problems on both the Tropospheric and the Stratospheric scale.

3. The Problems: 1- The Ozone layer which blocks most of the harmful UV radiation coming to the earth started to deplete. CFCs had the main contribution to this, because they aren’t washed out from the atmosphere. Eventually they move from the Troposphere to the Stratosphere, where the Ozone layer is. The CFCs release a Cl radical when exposed to UV light and this Cl radical causes the decomposition of Ozone(O3) into Oxygen(O2) and a ClO free radical. This ClO free radical reacts with an Oxygen free radical to make O2 and release another Cl which causes the same effect to happen again. The overall reaction of the break down of the Ozone by CFCs is given by: O (g) + O3(g) 2O2(g) (Cl Catalyst)

5. 2- Another problem is the stability of CFCs. Although many countries have signed a “CFC-free future” agreement, the CFCs long life span means that they will continue damaging the Ozone layer until they form another compound. • The search for a replacement is still on and is the major concern of many of the world’s nations. This is mainly because one Cl atom can destroy up to THOUSANDS of Ozone molecules before forming a different substance! • CFCs have been found to survive for 110 years in the atmosphere which makes many countries want to ban them completely.

6. 3- A third problem is that the release of CFCs increases the temperature of both the stratosphere and the troposphere as they absorb infra-red radiation and trap the heat inside their atomsand thus preventing the hot temperatures from escaping the earth’s atmosphere. CFC Concentration Stratosphere Temp Earth Temp