A layer of ozone has allowed life to thrive on Earth by protecting it from the ultraviolet radiations from the Sun. But the rising levels of pollution since the industrial revolution, particularly in the last one century, has resulted in the depletion of ozone in the stratosphere.
Ozone molecule is composed of three oxygen atoms bonded together. It occurs naturally high up in the Earth's atmosphere, where it protects the surface from harmful ultraviolet (UV) rays unless dissipated by natural or human phenomena. It is also considered a pollutant with adverse effects for humans and other creatures when present closer to the ground. The ozone layer is the common term for the high concentration of ozone that is found in the stratosphere between 15 and 30km above the earth’s surface. It covers the entire planet and protects life on earth by absorbing harmful ultraviolet-B (UV-B) radiation from the sun.
Atmospheric data demonstrates that ozone depleting substances are destroying ozone in the stratosphere and thinning the earth’s ozone layer. This is an annual phenomenon that takes place from September to early December when the westerly winds circulate all over the continent. The frigid temperature during this time, in combination with the Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) contained in the manufactured chemicals that are emitted from the surface of the Earth, trigger ozone depletion. High altitude clouds are formed as the temperature goes down. Chlorine and bromine react within these clouds in a photochemical process and destroy the surrounding ozone layer. The following entry of ultraviolet rays increases the chances of skin cancer and blindness in humans and sun damage in animals.
The hole that developed in the ozone layer over Antarctica was the smallest on record since the ozone hole was first discovered, according to scientists at NASA and the US National Oceanic and Atmospheric Administration. The appearance of ozone hole over the Antarctic mobilized international community into signing the Montreal Protocol in 1987.
The year 2019 recorded the smallest ozone hole in Antarctic since 1984, however, the detection of a rare ozone hole in the Arctic in the late March of 2020 has called for a re-evaluation of the progress made by Montreal Protocol.
The term "vortex" refers to the counter-clockwise flow of air that helps keep the colder air near the Poles. The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles. It always exists near the poles, but weakens in summer and strengthens in winter. Formation of polar vortex involves the accumulation of extremely cold air inside a ring of extremely strong westerly winds, also known as the Polar Night Jet. It appears in the upper stratosphere of both the poles every winter season. A strong polar vortex with high-altitude clouds is a fertile condition for the formation of the ozone hole.
