Context: Recently, The European Space Agency Copernicus Sentinel-5P satellite has detected a 26 million square kilometer giant hole in the ozone layer.
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Satellite measurements conducted over Antarctica have unveiled a gigantic hole in the ozone layer.
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Termed an “ozone-depleted area,” this region spans 26 million square kilometers (10 million square miles), approximately three times the size of Brazil.
About an Ozone Layer
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The ozone layer is a trace gas in the stratosphere, one of the four layers of the Earth’s atmosphere. It is found between 15 to 35 kilometers above Earth.
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Ozone creation: Ozone is composed of three atoms of Oxygen.The production of ozone in the stratosphere results primarily from the breaking of the chemical bonds within oxygen molecules (O2) by high-energy solar photons. This process, called photodissociation, results in the release of single oxygen atoms, which later join with intact oxygen molecules to form ozone.
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Good and Bad Ozone: Stratospheric ozone (Good Ozone) is formed naturally through the interaction of solar ultraviolet (UV) radiation with molecular oxygen (O2).
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Tropospheric or ground-level ozone (Bad Ozone), what humans breathe, is formed primarily from photochemical reactions between (VOC & NOX).
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Significance: It functions as a protective gas shield that absorbs ultraviolet radiation, protecting humans and ecosystems from dangerous amounts of UV radiation causing skin cancers.
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About Ozone hole
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By 1984, the ozone layer over Antarctica’s Halley Bay research station had lost one-third of its thickness compared to previous decades.
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The thinning of the ozone layer over Antarctica, came to be known as the ozone hole. The hole was caused by widespread use of chemicals called chlorofluorocarbons.
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Ozone Depletion: When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created.
What caused the Ozone hole this year?
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The size of the ozone hole over Antarctica fluctuates each year. The ozone hole opens up because of the rotation of the Earth causing special winds over the closed landmass of Antarctica. The winds create a mini climate, creating a shield over Antarctica preventing it from mixing with surrounding air. When the winds die down, the hole closes.
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Scientists believe this year’s big ozone hole could be due to the Hunga-Tonga- Hunga -Ha’apai volcanic eruptions. This eruption sent a lot of water vapor into the stratosphere.The water had an impact on the ozone layer through chemical reactions and changed its heating rate.
Conventions for Protection of Ozone layer
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Vienna Convention: First convention for the protection of the Ozone layer.
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To promote cooperation among nations by exchanging information on the effects of human activities.
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Montreal Protocol: Adopted in 1987, on Substances that Deplete the Ozone Layer. The landmark multilateral environmental agreement regulates the production and consumption of nearly 100 man-made chemicals referred to as ozone depleting substances (ODS).
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Kigali Agreement: Around 197 countries, including India, China and the USA, agreed at Kigali to reduce the use of Hydrofluorocarbons (HFCs) by roughly 85% of their baselines by 2045, by amending the 1987 Montreal Protocol.
Know About UV Radiation
Classified into three types as per wavelength: UV-A, UV-B and UV-C
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UV-A: Long-wavelength, 95% of the UV radiation reaching the Earth’s surface, high penetration power.
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UV-B: Short-wavelength that reaches the outer layer of your skin (the epidermis), Absorbed by the Earth’s ozone layer.
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UV-C: UVC radiation is the highest energy portion of the UV radiation spectrum; Blocked by the ozone layer.