Dear friends, our earth is the most beautiful and life-sustaining planet in our Solar System. A blanket of invisible air covers it. Clean air is important for all living things. It helps to nourish plants and ensures the safe existence of animals. All gasses and particles in nature, particularly air, work like a team so that we can enjoy life on earth.
Earth’s atmosphere is composed of a variety of gases and other small particles. The most common gases in the air are nitrogen, oxygen and argon. In the air, oxygen is present in three different forms — oxygen atoms (O), as oxygen molecules (O2) and as ozone (O3).
Earth and the sun
We all know that earth receives light from the sun. Without the sun, earth would be dark and cold. The sun warms our seas and makes our seasons. Plants and trees also need sunlight for growth.
The sun emits two types of rays, infrared rays and ultraviolet rays. Infrared rays are visible to us and important to maintain life on earth, on the other hand, ultraviolet (UV) rays are both harmful and helpful for us. We cannot see these UV rays and they are of different types, just like visible light. The most common types are called UVA and UVB.
The UVB rays are harmful for all of us. The atmosphere offers resistance against this constant bombardment of harmful UV radiation before they reach earth’s surface, with the help of the ozone layer. Most UVB is absorbed by the ozone layer, so 99 percent of the ultraviolet radiation that reaches earth’s surface is UVA.
Ozone layer is an earth protector
When sunlight strikes the oxygen in the air, it splits it into three parts. One part of the oxygen then combines with two parts of other oxygen atoms (1+2) and forms a new team known as ozone. Ozone is of blue colour and is found on the earth’s upper atmosphere.
Large amount of tiny ozone gas particles combine to form a thin and invisible ozone layer, on the upper edge of the earth’s atmosphere. This ozone layer protects us from dangerous sunrays, just like umbrellas and hats protect us from the rain and the sun.
This layer is very fragile and can be damaged easily. In 1985, a hole in the ozone layer was discovered above the Antarctic.
What harms the ozone
The hole was the result of the reaction of harmful chemicals and gases on the ozone layer.
The biggest enemy of the ozone layer is a group of chemicals referred to as CFCs. It is composed of chlorine, fluorine and hydrogen. The CFHs slowly travel to the upper surface of earth’s atmosphere and when it comes near the ozone layer, sun’s rays separate chlorine. This chlorine destroys the ozone layer and makes a hole in it, allowing harmful ultraviolet rays to reach the earth.
Old refrigerators, air conditioners, perfumes, hairsprays, deodorants and household chemicals, contain high amount of CFCs.
The second enemy of the ozone layer is methyl bromide, a colourless and odour less gas. Farmers use it to kill a wide variety of insects, spiders, mites, nematodes, rodents and flies that harm plants and trees.
‘Halon’ or ‘halogenated hydrocarbon’ is a liquefied gas that stops the spread of fire. It is the main ingredient of fire extinguishers but it is also harmful for the ozone layer.
Laughing gas or nitrous oxide is also considered to lead to the thinning of the ozone layer. Fertilisers and fossil fuels are common sources of nitrous oxide.
The sun’s rays, when they reach earth, react with the fumes, smoke and gases coming out from cars and factories, and form ‘bad ozone’. This bad ozone is harmful and can cause lung diseases, damage our crops and trees, and creates fumes all around us known as smog.
Ozone layer protects us from diseases
When there is a hole in the ozone layer, the harmful ultraviolet B rays easily reach the earth’s surface. These harmful UVB rays can cause skin cancer, damage the eyesight and the immune system. In addition, it can make our skin thick, wrinkled and gloomy and it can also forms rashes on fair-skinned people.
Protect yourself from sunrays
The ozone layer protects us from most UV rays, but not all of them. Some UV rays still escape, therefore we need to be protected from them.
To protect yourself from harmful effects of UV rays, never leave home without applying sunscreen. Wear protective clothing, such as a long-sleeved shirt, pants, a wide-brimmed hat and sunglasses, when you go outside. Avoid the sun from 10am to 4pm, during the hours of the day with maximum UV rays emission. It is important not to stay with the sun overhead and to seek shade as often as possible so that our skin and eyes are not burnt by UV rays.
Water, snow and sand reflect the damaging rays of the sun, which can increase your chances of sunburn.
Countries most at risk
Australia, New Zealand, Argentina, Chile, Russia and South Africa are countries most at risk from ultra violet rays from the sun because of the damage to the ozone layer.
Published in Dawn, Young World September 23rd, 2017