Have you noticed people wearing large hats and sunglasses to protect themselves from the sun? Many people often carry umbrellas to shade themselves. The white face paint cricketers paint their faces with, isn’t just out of style. That’s sunscreen! Sportsmen cover their faces with sunscreen before they step out to play. Why do we need protection from the sun? Isn’t sunshine good for us? Well, yes mostly. But there are some ultraviolet rays that the sun radiates that are not good for us at all. These ultraviolet rays from sun can damage our skin cells by causing sunburn and skin cancer.
Our Earth to a large extent shields us from these ultraviolet rays. How? Earth has a protective layer all around it that absorbs most of the UV rays. This protective layer is known as the ozone layer. It is made up of a gas called ozone. Ozone is formed when sunlight hits the oxygen molecules present in the earth’s atmosphere and changes them (makes them O2 from O3). These ozone molecules are capable of absorbing the ultraviolet rays.
Did you know that ozone means smelly in Greek? Ozone is a pretty smelly gas so we should be glad that the ozone layer is tucked far away in the Stratosphere, the second layer in our the earth’s atmosphere. Stratosphere has most ozone molecules and thus have the ozone layer.
Sadly, the ozone layer is getting impaired. You might have heard about holes in the ozone layer? There are no holes but it means that at that particular place the ozone layer has thinned down considerably. A large area of ozone layer over the Antarctic has thinned down over the years. It is known as Antarctic ozone hole. The damage of ozone layer started with the use of Chlorofluorocarbons or CFC’s. Chlorofluorocarbons are chemicals made up of combination of chlorine, fluorine and carbon. CFC’s when come in contact with ozone molecules destroy them. They were used in aircraft, ships, and large vehicles in 1940’s in world war II. Later in 1960, CFC’s were used a lot in refrigerators and air conditioning. The fact that CFC’s are depleting the ozone layer was discovered only in 1974 by scientists Sherry Rowland and Mario Molina. It was not until 1987 that the use of CFC’s was fully banned. Sadly CFC molecules once released can stay in the atmosphere for even 100 years So it will take many more years to eradicate the damage.
We can not turn back time. But there are few things we can do on our part.
- We must stop use of any refrigerators and ACs manufactured before 1994.
- We should pollute our environment less. We can reduce the use of car and use alternative means of transport.
- We should avoid using aerosols, sprays, fire extinguishers composed of chlorofluorocarbons.
Any long journey begins with the first step. So why don’t you start now?