Ozone Depletion

Ozone Depletion 

• The atmosphere of the Earth is divided into 5 laverrs, From closest to farthest layers are troposphere.stratosphere, mesosphere, thermosphere and exosphere. 
• The majority of dhs msphere's pzone remains stratosphere, whichextends from 10 kms above the Eath's surface to 50kms. The earth's stratospheric ozone layer plays a critical roll in absorbing ultra violet radiation emitted by our sun and protects the Earth from the harmful effect of ulraviolet rays: otherwise it causes skin cancer of human and can lead to genetic damage 
• (A)5smcs Hence, the ozone layer is essential to life earth, as it absorbs harmful ultraviolet-B radiation Irom the sun. In recent years the thickness of this layer has been decreasing, leading to create holes in the layer is called ozone depletion. In the last thirty years, it has been discovered that stratospheric ozone is depleting as a result of chlorine and bromine based pollutants 
• Every chlorine atom can destroy up to 100 000 azone molecules Oone depletion occurs when the nafural halance between the production and Jestruction of striatosphenic ozone is stopped The main ozone depleting substances are 
• (i) Chlorofluorocarbons-it is used as coolants in refrigerators,freezers and air conditioners in buildings and cars 
• (li) Halons-it is used in some fire extinguishers, in cases where materials and equipment would be destroyed by water or other fire extinguisher chemicals.
• (iiMethyl Chloroform-it is used mainly in industry for reducing vapour, some aerosols,cold cleaning,adhesives and chemical processing 
• (iv) Carbon Tetrachloride-it is used in solvents and some fire extinguishers. 
• Chlorofluorocarbons (CFCS)are main substance causing ozone depletion, accounting for over 80% of total stratospheric ozone depletion CFCS are not destroyed reactions with ocher chemicals or washed back to Earth by rain. They simply do not break down in the lower atmosphere and they can remain in the atmosphere 120 Finally, they are transported into the stratosphere where they broken down by ultrayiolet (UV) rays from the Sun,releasing free chlorine. The chlorine becomes actively involved in the process of destruction of ozone. The net result is that two molecules of ozone are replaced by three of molecular oxygen, leaving the chlorine Ozone is converted to ygen. leaving the chlorine atom free to repeal the process up to 100,000 times, resulting in areduced level of ozone alin increase mo w hum. 
• CI+O,CIO+0, 
• CIO+OCI+0 
• There are a number of things that we as individuals can do to protect the ozone layer These include proper disposal of old refrigerators,the use of halon-free fire extinguishers and the recycling of foum and other non-disposable packagingAlso, if emissions of ozone depleting substances are now being controlled. 
• the ozone layer is not likely to fully repair itself for everal decades. Consequently, we should take precautions when exposing ourselves to the San.