The depletion of the ozone layer is a phenomena that was observed during the later part of the 70’s. Since then, it’s showed a declining rate of 4% per decade and there is a remarkable decrease over the polar regions of the Earth. The main reason for the destruction of the ozone is by man-made halocarbon refrigerants such as CFCs, halons and freons that are released into the atmosphere. These elements are known as “ozone depleting substances” or ODS. These harmful substances strike the ozone and splits it apart. The ozone depletion has led to a worldwide concern as the thinning protective coat over Earth is letting harmful ultraviolet light pass which has led to many health hazards like skin cancer, damages to plants and plankton as well as cataracts. Therefore many governments have banned products that produce these ODS.
The ozone layer is our warrior against the might Sun that is bombarding earth with harmful UV radiation and we are trying our best to protect it. Ozone is basically a gas also referred to as O3 which is formed and reformed constantly in our Earth’s atmosphere. If it were not for the ozone layer, our Earth would be barren with slight traces of life. It is also being said that the southern hemisphere of the Earth could have an additional 20% depletion of the ozone that could result in natural calamities like tornadoes, avalanches, fires, tsunamis etc.
The Main Ozone Depleting Substances:
- Chlorofluorocarbons (CFCs)
- The most widely used ODS, accounting for over 80% of total stratospheric ozone depletion.
- Used as coolants in refrigerators, freezers and air conditioners in buildings and cars manufactured before 1995.
- Found in industrial solvents, dry-cleaning agents and hospital sterilants.
- Also used in foam products — such as soft-foam padding (e.g. cushions and mattresses) and rigid foam (e.g. home insulation).
- Used in some fire extinguishers, in cases where materials and equipment would be destroyed by water or other fire extinguisher chemicals. In B.C., halons cause greater damage to the ozone layer than do CFCs from automobile air conditioners.
- Methyl Chloroform
- Used mainly in industry — for vapour degreasing, some aerosols, cold cleaning, adhesives and chemical processing.
- Carbon Tetrachloride
- Used in solvents and some fire extinguishers.
- Hydrofluorocarbons (HCFCs)
- HCFCs have become major, “transitional” substitutes for CFCs. They are much less harmful to stratospheric ozone than CFCs are. But HCFCs they still cause some ozone destruction and are potent greenhouse gases.