Depletion of Ozone Layer:

Since  the last decade or so, there is concern about the possible reduction in the ozone layer surrounding  the earth. Now the question arises, what had led to the depletion of this layer. The reasons are many. The foremost is the widespread usage of chlorofluorocarbons. These are gases which readily liquify when compressed. This makes them useful as refrigerants, propellants in aerosol cans, and in plastic foams. Chlorofluorocarbons are very stable and accumulate  in the atmosphere, where they react with ozone. Nitrogen oxides also play a significant  role in ozone destruction. It is being felt that the introduction  of more nitrogen oxides  into  the upper atmosphere by  jet planes flying there could decrease the ozone to dangerously  low level. The fear is that chlorofluorocarbons will deplete the ozone layer and allow more ultraviolet radiations  to reach the earth's surface. An  increased level of ultraviolet radiations would cause more skin cancer, affect crops, interfere with oxygen cycle and even distoti weather patterns.