Ozone Layer

The ozone layer is the protective cover of air in the stratosphere or the blanket that protects the organisms living on the planet. Let us learn more about this protective cover and the ozone layer depletion. 

What is the ozone layer?

The ozone layer is the result of some chemical reactions in the atmosphere initiated by sunlight. The chemical reaction happens when the sunlight hits the oxygen molecules. The oxygen molecules split into single oxygen atoms. Now, these single oxygen atoms combine with oxygen molecules (O2 molecules), which results in the formation of O3 molecules. The layer of O3 molecules is called the ozone layer. 

The ozone layer is majorly situated in the stratosphere layer. However, sometimes it also comes in the troposphere layer. The troposphere has only about 10% of the total ozone layer. The ozone in the troposphere is for a short period.  

Importance of ozone layer

It is the product of the reaction of sunlight with oxygen molecules. Ozone is a greenhouse gas and like other greenhouse gases, its molecules possess the quality to capture and store warmth. 

The ozone layer is at the highest altitude of the atmosphere. So, before the sunlight hits the earth’s surface, it has to first pass through the mighty ozone layer.

The ozone layer filters the sunlight and blocks the harmful UV rays from entering. UV rays have been proven to be potentially dangerous to life on earth. Exposure to UV rays could have hazardous effects on human life. It increases the chances of skin cancer and skin burn in humans. Also, they have harmful effects on the eyes. This is the importance of the ozone layer!

Ozone layer depletion 

The advancement in technology to live an easy and relaxing life started showing its side effects in 1985. Scientists found out about the ozone hole in the Antarctic region. Various researches were conducted to find out the actual reason behind the vanishing of the ozone layer. 

The reasons were the production of complex CFCs (Chloro-Fluorocarbons) and HCFCs (Hydro-Chloro-Fluorocarbons). They were released into the atmosphere by refrigerators, air conditioners, fire extinguishers, foam, and aerosol propellants. The use of methyl bromide for the fumigation of soil and structures also played a role in the cause of depriving the ozone layer. 

The production and import of ozone-depleting substances are looked at and taken care of by the Montreal Protocol. Other substances also affect the ozone layer. However, their effects on the ozone layer could hardly be noticed. That’s why they don’t count under the Montreal Protocol. 

Ozone-depleting substances (ODSs) 

Ozone-depleting substances help in the cause of destroying the shield that protects the habitats of earth. Some of them are: 

• Chlorofluorocarbons (CFCs)
• Halon 
• Carbon tetrachloride (CCL4)
• Methyl chloroform (CH3CCL3)
• Hydro-Bromo-fluorocarbons 
• Hydro-chloro-fluorocarbons
• Methyl bromide 
• Bromo chloromethane 

Ozone hole   

In 1985, the brilliant scientists- Brian Gardiner, Joe Farman, Jonathan and  Shanklin revealed a massive decrease in the levels of the stratospheric ozone layer. It was recorded over the Antarctic region. 

It usually happens at the start of the Southern hemisphere, spring in August. The ozone hole is the thinning of the ozone layer because of the cold temperatures. 

The occurrence of the ozone hole has been an annual activity for the last 40 years of human history. In 2020, a record-breaking arctic ozone hole was noticed. The complex chemicals released by humans travel to the stratosphere and gather inside the polar vortex. It then begins to shrink in size as the warm summer season approaches.

The polar vortex is nothing but a phenomenon when a jet of cold wind swirls above the low-pressure area in the polar region.  In winters, this polar vortex in the North Pole expands. Then, as a result of this phenomenon, subsequent cold air is generated. It travels its whole way through the South Pole. In the stratosphere, the temperature starts to rise which subsequently weakens the polar vortex. By the end of December, everything gets back to normal. 

Conclusion

The ozone layer, which is 15 miles above the surface of the Earth, safeguards life on the planet by absorbing the sun’s strongest ultraviolet radiation. When the ozone layer thins (depletes), more UV light reaches Earth than is normally recorded, increasing Earth’s temperature and thus, increasing the risk of sunburn and skin cancer.