Ozone depletion and its consequences-The Frontier Post [Archive] By Waqar Hussain

Science has progressed astonishingly in the recent years. It has completely mechanized this world and is stepping to hold nature under its thumb, but all these blessings seem to be a Pandora's• box; the sidelined complications of various inventions are far more threatening than their rewards. It is rightly said: In nature there are neither rewards nor punishments, there are only consequences. National Aeronautics and Space Administration (NASA) has recently stated that ozone layer is corroding much quicker than is estimated by the world scientists. Here are some facts about the ozone layer and its depletion. These will help in starting the campaign against forthcoming An oxygen molecule comprises of two atoms while ozone has three atoms. Oxygen and ozone are allotropic forms, abbreviated as 02 and 03 respectively. Oxygen is a colorless and odorless gas. Ozone is a blue-colored, pungent-smelling gas. The action of electric charge converts oxygen to ozone but the former is more stable. The shape of both molecules is pictured below:-Oxygen (02) ozone (03 ) Nature has provided a thick layer of ozone in upper atmosphere enclosing the earth. It blocks the dangerous ultra-violet (UV) radiation from reaching the earth and acts as a protective shield for the biosphere. Ozone belt is preset in atmosphere between 10-30 miles from the earth. Ultra-violet radiation causes diseases of eyes (e.g. cataract), skin cancer, premature signs of old age and weakens our defense mechanism against diseases. These rays also affect plants, kill the plankton and reduce the yield of crops. The low production of crops in Australia and the Argentina is attributed to be the effect of UV rays. These countries also have a high ratio of cancer patients. It is estimated that 10% reduction of ozone caused 20,000 skin cancer only in the USA. The cause of depletion of ozone is due to presence of chlorofluorocarbons (CFC) in the atmosphere. Chlorine atom, which is the part of CFC, disintegrates ozone molecules. How do they reach the ozone layer? The answer is: CFCs manage their way to the upper part of ozone layer as they remain unreactive on the earth and lower part of ozone layer. In the upper part of the belt, UV rays interact with CFCs and liberate chlorine which reacts chemically with ozone to form oxygen and chlorine-monoxide: CFC +03 U.V. rays, CLO + F.0 This chlorine-monoxide react chemically and release chlorine again. In this way just one chlorine atom destroys one lakh ozone molecules. It is evident that ozone layer can be protected if chlorine is stopped from reaching it. 'Chlorine maneuvers to get as far in the flying saucer of CFCs. We can also say that CFC stands for Chlorine's Flying Car. So the use of CFC must be restricted or abolished; there is only Hobson's choice. By 1975, the chlorine concentration was 1.4 parts per billion, now it is just under 3 enough to create holes in the ozone layer. The first hole was discovered above the South Pole arid was called the Antarctic Hole, with a size equal to that of USA. The second hole is above the Antarctic Ocean. Chlorofluorocarbons are used in a billion refrigerators and car air-conditioners of the world. They are widely used in manufacture of plastic, foam, pesticide, perfumes etc. If countries are grouped according to the use of CFC the first would contain the USA, former USSR, Japan, European countries etc. The second group comprises Canada, Brazil, Australia, South Africa, Pakistan, China etc. The list of third group is quite long. The production of CFCs by the USA and European countries is 7,50,000 tones. Former USSR alone has a figure of 60,000 tones. This shows which countries are responsible for hanging the sword of Damocles over the entire world. The world is striving to save the ozone belt. The advanced countries are planning to manufacture refrigerators and air-conditioners without CFC. The refrigerators already in use will be destroyed after capturing CFC. In this way, CFC will not be able to reach the atmosphere. The US government has enforced a law saying that refrigerators which have ceased to function normally will not he allowed to be disposed of without taking possession of CFC first. Scientific analysis reveals that the CFCs already present near the ozone will remain active for a hundred years. It means if we abolish the use of CFC, the escaped CFC will continue to eat up ozone for the next hundred years. The question arises whether nature has any arrangement for the production of ozone to compensate this loss. The answer is, yes. Ozone is produced on the earth by the interaction of sunlight and hydrocarbons. But it has a weak chemical bond and it suddenly transforms info stable oxygen. Even if it doesn't convert into oxygen, it is very difficult for ozone molecules to reach the layer. In the stratosphere, UV light interacts to produce ozone but in a quantity far less than is being destroyed. It is imperative to mention that chlorine used .to clean water is not dangerous for- ozone as it cannot reach the upper atmosphere. These chlorine's and chlorides react with water and other elements to form different compounds and remain on the earth. There are some precautionary measures which must be adopted to minimize the effect of UV rays. * During noon time, exposure to sun-rays must be avoided. * Ears must be covered by a cap or cloth to protect for direct sunlight. * During peak hours of day sunglasses must be used. The abolition of use of CFC, adoption of precautionary steps, patience and perseverance are required to retrieve the lost position and a lesson to learn. In nature there are neither rewards nor punishments, there are only consequences.

 WAQAR HUSSAIN,

 Lahore.