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ozone — English
Triatomic oxygen (O3) which forms in the upper atmosphere at about 20-25 kilometres above the surface of the Earth. (Note that the oxygen we breath is molecular oxygen, that is O2). Ozone forms as a result of the dissociation of some molecular oxygen and the “loose” atoms then combine with proper oxygen molecules to form triatomic oxygen. Below the level where ozone is formed, it gradually disperses toward ground level and on the way down the triatomic ozone quickly changes to normal oxygen molecules. Ozone is important to us because it readily absorbs ultra-violet radiation and thus prevents a large amount of the ultra-violet rays from the sun to reach the Eearth’s surface. Ozone actually protects us from recieving too much ultra-violet radiation (which could cause skin cancers and eye cataracts). During the late 1960s and early 1970s, we detected a dramatic reduction of the ozone in the upper atmosphere. Since we were releasing large volumes of chlorofluorocarbons (CFCs) into the atmosphere and knew that CFCs dissociate ozone, we deduced that air pollution was causing this reduction in atmospheric ozone. Realising the consequences of too little ozone in the atmosphere, an international convention (see “international convention”) was held in Montreal, Canada. The Montreal Protocol was ratified in 1987 which immediately placed a total ban on the release of CFCs. Even before all the stipulations of the Montreal Protocol (Accord) could be implemented, the depleted ozone layer started returning to its former condition. Since then we have discovered that the ozone concentration in the atmosphere increases and decreases as a result of currently unexplained natural causes. We do not know what effect the Montreal Accord had on the ozone layer, but we have at least succeeded in reducing the amount of CFCs released into the atmosphere and learnt that humans could act together to achieve some environmental goal, provided the alternative is too serious to risk.
