1.0     INTRODUCTION

Ozone is a green house gas which absorbs the sun’s harmful ultraviolet light that can cause skin cancer; weaken the immune system, damage plants and marine creatures from entering the earth’s atmosphere. (Defabo et al., 1979, Yukio Takizawa 1990).

The ozone layer is a layer in earth’s atmosphere which contains relatively high concentrations of ozone. This layer absorbs 97-99% of the sun’s high frequency ultraviolet light, which is potentially damaging to life on earth. (Lubin et al., 1989, Fredrick et al 1988).

The ozone layer is threatened by a range of chemicals usually referred to as ozone depleting substances (ODS) which destroys the layer through a series of chemical reactions. These chemicals such as chlorofluorocarbons (CFCs), methyl – bromide etc. are released into the atmosphere owing to various activities caused by man such as the use of refrigerants (which release cfcs) and insecticides (Siedel and Daniel 1990).

Ozone layer depletion leads to thinning of the ozone layer thereby exposing the organisms on earth to harmful ultraviolet radiation and increase in global temperature with adverse effects on man, (Leading to skin cancer, eye disorders, immunological effects), aquatic life and land vegetation (Joe Buchdahl, 2002).      

Ozone layer is also a deep layer in earth’s atmosphere that contain ozone which is a naturally occurring molecules containing three oxygen atoms. These ozone molecules form a gaseous layer in the earth’s upper atmosphere called stratosphere. This lower region of stratosphere containing relatively higher concentrations of ozone is called Ozonosphere. The ozonosphere is found 15-35km (9-22miles) above the surface of the earth. The average concentration of ozone in the atmosphere is around 0.6 parts per million. The thickness of the ozone layer differs as season and geography. The highest concentration of ozone occurs at altitudes from 26-28km (16-17miles) in the tropics and from 12-20km (7-12miles) towards the poles (Britannica 1992).  

 The ozone layer forms a thick layer in stratosphere, encircling the earth that has large amount of ozone in it. It protects our planet i.e earth from the harmful radiations that comes from the sun. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henry Buisson. The ozone layer has the capacity to absorb almost 97-99% of the harmful ultraviolet radiations that sun emits and which can produce long term devastating effects on human beings as well as plants and animals (Coohill, T.P 1991).