EEN 100:ENVIRONMENTAL EDUCATION
Ozone layer is a deep layer in the stratosphere, encircling the earth that has large amounts of ozone in it. Ozone is a colourless gas found in the upper atmosphere of the earth that is formed when oxygen molecules absorbs ultraviolet, and undergo a chemical reaction known as photo dissociation or photolysis.
In this process, a single molecule of oxygen breaks down into two oxygen atoms.The free oxygen atom[o],then combines with an oxygen molecule and forms a molecule of ozone.The ozone molecule in turn absorbs ultraviolet rays between 310-200nn[nanometer] wavelength and thereby prevent these harmful ...view middle of the document...
CFCs amounts to almost 80% of the total depletion of ozone.Other ozone depleting substances[ODS] are hydrochlorocarbons[HCFCs] and volatile organic compounds[VOCs] found in vehicle emission,byproducts of indrustrial processes,refrigerants and aerosols.
Ozone depleting substances are relatively stable in the lower atmosphere of the eaqrth,but in the stratosphere,they are exposed to ultraviolet radiatinon and thus they break down to release a free chlorine atom.This free chlorine atom reacts with an ozone molecule and forms chlorine monoxide[CLO] and a molecule of oxygen.Thereafter CLO reacts with an ozone molecule to form a chlorine atom,and two molecule of oxygen.The free chlorine molecule again reacts with ozone to form chlorine monoxide.The process is a continous one and this results in the depletion of ozone layer.
As ozone layer depletes in the stratosphere,it forms a hole in the layer.This hole enables harmful ultraviolet rays to enter the earth atmosphere and these ultraviolet rays are associated with a number of health-related and environmental issues.The depletion leads to harmful human health in that they cause more skin cancer,sunburns and leads to premature aging of the skin.
They also lead to more cataracts,blindness and other eye diseases;UV radiation can damage several parts of the eye including the lens,cornea,retina and conjunctiva.Cataracts[a clouding of the lens] are major cause of blindness in the world.A sustained 10% thinning of ozone layer is expected to result in almost two million new cases of cataracts per year globally.
The overexposure of UV rays also weakens the human immune system[immune suppression].Early findings suggest that too much UV radiation can suppress the human immune system which may play a role in the development of skin cancer.
Ozone depletion also has adverse impacts on agriculture,forestry and natural ecosystem.Several of the world major crop species are particularly vulnerable to increased UV,resulting in reduced...