Have you ever wondered why cricketers paint their faces white? Or why your mother insisted that you put on sun screen lotion before stepping out every summer? The answer is UV rays.
Though the sun plays a vital role in our lives by providing light and energy, there are some sunrays that can be harmful.These sunrays can increase the risk of skin cancer, cataract and harm the immune system. They can also damage terrestrial plant life, single cell organisms, and aquatic ecosystems. These harmful sunrays are called Ultra Violet (UV) rays.
Life on earth is protected from the UV rays by a layer in the upper atmosphere knows as the stratosphere which surrounds earth. This layer is called the Ozone layer.
Ozone is a gas made up of three oxygen atoms(O3)much like the layer of butter that settles on top if a glass of buttermilk is left unattended for a while.This layer is just about 3-5mm thick. This thinly spread-out gas has been protecting life near the earth’s surface from the sun’s harmful UV rays for billions of years. Ozone is spread thinly throughout the stratosphere in low quantities.
Why is the Ozone Layer in danger?
Our ozone shield is now being deteriorated due to certain man-made chemicals,primarily chlorofluorocarbons(CFCs) and nitrogen oxides. CFCs are a group of chemically similar gases used in refrigeration systems, air conditioners, aerosols, solvents and in the production of some types of packaging.Nitrogen oxides are a by-product of fuel burning,for example:aircraft exhausts.
What is the Ozone hole?
The ozone hole is not literally a ‘hole’ but an area wherein the total ozone amount is less than 220 Dobson Units. This depletion of the ozone layer occurs during spring time in the Southern Hemisphere between the months of August and October.
Though the ozone layer globally is in danger, the layer above Antarctic is in greater danger as it is fast depleting. It takes only a small amount of CFCs to destroy an awful lot of ozone.
The ozone hole has steadily grown in size up to 27 million sq. km
Can we stop the depletion of Ozone Layer?
Yes we can! All we have to do is to reduce the production of those chemicals that cause the destruction of ozone, like CFCs and nitrogen oxides. In 1987, the Montreal Protocol was signed by many nations whereby those nations that signed agreed to reduce their emissions of CFCs to a half by 2000. Worldwide standards for air-conditioning equipments are being modified and a new substance called HFC (hydro fluorocarbons) is being used instead of CFC. So, encourage your parents, relatives and friends to make sure their refrigerators and air conditioners do not have CFCs.
Find out the name of the scientists who discovered a recurring springtime Antarctic ozone hole. Find out about ozone gas that can be dangerous to our health.
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