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Ozone Layer Depletion-A Threat to Mankind

Ozone layer depletion is a common topic, everyone has heard about it. Yet many people have a misconception about it. Some people think that ozone layer depletion itself causes global warming. Others think that it cannot stand the heat and the rise in global temperature is destroying it. I am going to answer some common questions about the ozone layer like - What is the ozone layer. Where is it found? And most important, why is it depleting?


What is the ozone layer?

We apply sunscreen while going to places where it is sunny. The sunscreen protects us from the harmful radiation coming from the sun. In the same way, the ozone layer is like a sunscreen that protects the creatures on the earth from ultraviolet [UV] rays of light coming from the sun. The ozone layer is made up of highly reactive molecules called ozone. Each ozone molecule is made up of 3 oxygen atoms. The ozone layer absorbs about 98% of the UV radiation from the sun, doing its job efficiently. So even if the ratio of ozone molecules to all other air molecules is 3:10,000,000, we are safe from harmful radiation [at least until we hadn’t depleted the ozone layer, but that’s a different topic]. Where is the ozone layer?

The atmosphere is divided into 6 parts. The ozone layer is found in the 2nd part called the stratosphere, which is 15 km-30 km above the earth. Funny enough, while the stratosphere is about 15 km thick, the ozone layer is only 3-5 mm thick. Pretty small, isn’t it?



Why is the ozone layer depleting?

All was fine until the 19th century. As the 20th century started, and civilization developed, the actual problem began. Some materials such as refrigerators, air conditioners, plastic products, etc. emitted chemical compounds called chlorofluorocarbons or CFCs. A CFC molecule contains the elements- carbon, chlorine, and fluorine. When these CFCs came in contact with ultraviolet rays, they broke down into compounds containing chlorine. When these chlorine-containing compounds came in contact with ozone molecules from the ozone layer, they basically broke the molecule. You might be wondering if there was a chance that a CFC molecule never came in contact with an ozone molecule before degrading itself. Well, a CFC molecule is a stable compound that can last for even a hundred years. This high lifespan means that a CFC molecule will most likely not destroy 0 or 1 ozone molecule, but more than 1000 ones.


Why is this a threat?

When ozone holes [thinner patches of ozone layer] are formed due to degradation of the ozone layer, ultraviolet rays have a place to enter. Ultraviolet rays can cause skin cancer, quick aging, sunburns, eye cataracts & damage to the immune system. In 1989, the Montreal Protocol, which banned the use of ozone-depleting substances, was issued internationally. Since then, the usage of ozone-depleting substances has been reduced. Still, the ozone layer hasn’t healed completely, and as responsible civilians, we should dispose of old vehicles, refrigerators, and air conditioners, the least we can do, to protect the ozone layer.


Did you know that ozone means ‘smelly’ in Greek, as the gas has a strong smell?