Confinement of ozone hole mainly in the Antarctic stratosphere to protect the living kingdom on the earth: chemistry behind this Nature’s unique gift

• Published in: Chemistry Teacher International
• Main Authors: Das Udita, Das Ankita, Das Asim K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: De Gruyter 2023
• Subjects: antarctic ozone hole; chapman ozone cycle; chlorofluorocarbons (cfcs); polar stratospheric cloud (psc); stratosphere; uv radiation; Chemistry; QD1-999; Antarctic; Arctic; The Antarctic; Antarc*; Antarctica
• Online Access: https://doi.org/10.1515/cti-2023-0006; https://doaj.org/article/b11536a46fdc4e309904ffc94c077e6d

Man-made activities can release the ozone depleting substances (ODSs) like chlorofluorocarbons (CFCs) and other halocarbons stable in atmosphere and ultimately, they migrate to the stratosphere where they can destroy the ozone layer through the XOx catalytic cycle (X = Cl, Br). The active forms in this catalytic cycle are X and XO that can be arrested in the inactive forms like XONO2 (halogen nitrate, an additive compound of two odd electron molecules XO and NO2) and HX (produced in the reaction of X with CH4) in the stratosphere to prevent the ozone depletion cycle. The catalytically active forms from these inactive species can be regenerated in the reactions on heterogeneous solid surface like polar stratospheric cloud (specially Type II PSC formed at about −85 °C). Formation of such PSC in the stratosphere is only possible in the supercooled stable Antarctic vortex produced in the prolonged winter. In fact, formation of such PSC in the stratosphere is not possible in the other regions of the earth and not even in the Arctic pole where no stable Arctic vortex is generally formed in the winter. Thus nature confines the ozone depletion reactions mainly in the stratosphere of Antarctica pole which is practically inhabited.