Atmospheric Structure and Ozone

Chlorine free radicals act as catalysts in the stratosphere, where they react with ozone (O3) to form oxygen (O2) and chlorine monoxide. This process destroys ozone molecules, which is the primary cause of ozone layer depletion.

Scientific evidence regarding the depletion of the ozone layer, particularly the role of CFCs, gained significant attention and was widely published in the 1980s following the discovery of the Antarctic ozone hole in 1985.

Chlorofluorocarbons (CFCs) and carbon tetrachloride (CCl4) are both significant ozone-depleting substances. Carbon tetrafluoride (CF4) is also recognized as a greenhouse gas with potential atmospheric impacts, making all listed options contributors to the broader issue.

Ozone depletion in the stratosphere has resulted in formation of a large area of thinned ozone layer, commonly called as the ozone hole. UV radiation of wavelengths shorter than UV-B, are almost completely absorbed by Earth's atmosphere, given that the ozone layer is intact. But, UV-B damages DNA and mutation may occur. It causes aging of skin, damage to skin cells and various types of skin cancers. In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called as snow-blindness, cataract, etc. Such exposure may permanently damage the cornea. Thus, the correct answer is option D.

Ozone layer is a region of concentration of ozone molecule. $O _3 (O _2+ O)$ in the earth's atmosphere. The layer lies in the stratosphere at an altitude of 18-50 kms. The ozone layer naturally Shields earth's life from the harmful effect of the Sun's ultraviolet radiations.

The UV-C radiations breakdown the bonds in the chlorofluorocarbons (CFCs) to release the chlorine monoxide and the nascent chlorine. These further react with the ozone to split it into ordinary oxygen molecules. The oxygen molecules are further broken down into nascent oxygen, which acts as the radicle. 

Polar spring, also known as the Antarctic Spring is the period from late August to early October and the strong westerlies circulate around the Antarctic continent creating a polar vortex. The polar vortex results in the formation of the polar stratospheric clouds which trap most of the gases including the ozone-depleting factors like CFCs, methyl bromide etc. 

In the stratosphere of the atmosphere, the UV rays are concentrated and these react with the oxygen to produce the ozone. This ozone persists in the form of the ozone layer and acts as the absorbent for the UV rays. Ozone layer does not allow the UV-B and UV-C from hitting the earth's surface, thereby preventing the various harmful after effects. Sulphur dioxide, carbon monoxide and methane are the primary pollutants of air.

Chlorofluorocarbons are the halogenated paraffin hydrocarbons containing chlorine, fluorine and carbon. These have been extensively used as the refrigerants and the spray propellants due to their non-toxic nature. But, the CFCs have found their way to the stratosphere of the atmosphere where the incidence of the UV rays is very high. The CFC splits up when exposed to the UV rays and release the reactive chlorine species. This is harmful to the ozone in the stratosphere because the chlorine reacts with ozone to release the simple oxygen, that is further converted to the reactive nascent oxygen.

The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). These compounds are transported into the stratosphere by the winds after being emitted from the surface.[2] Once in the stratosphere, they release halogen atoms through photodissociation, which catalyze the breakdown of ozone (O3) into oxygen (O2).[3] Both types of ozone depletion were observed to increase as emissions of halocarbons increased.

Oxides of nitrogen find their way to the environment when they are released from the fertilizers, farms, combustion of coal etc. These bear a similarity to the paraffinated halogens like the chlorofluorocarbons when they reach the stratosphere of the atmosphere. They get unstable when exposed to the UV rays and the reactive nitrogen atom recs with the ozone to form the nitrogen dioxide and the diatomic oxygen molecule, similar to the reaction catalysed by the CFCs which release reactive chlorine that break down the ozone.

Ozone is found in high concentration in the stratosphere of the earth's surface in the form of ozone blanket or commonly known as the ozone layer. The vital function of ozone is to absorb the sun's ultraviolet radiation before it reaches the ground hence protecting the earth from its harmful effect. But the ozone-depleting substance such as Chlorofluorocarbons, nitrous oxides, etc that reacting with the ozone layer cause depletion of it forming ozone hole.

Among the five layers of the earth's surface ozone is present in the stratosphere which absorbs UV radiation before it reaches the ground. The main cause of ozone depletion is manufactured chemicals especially CFCs, these compounds reach the stratosphere by winds, where they release halogen atoms through photodissociation and cause the breakdown of ozone into oxygen. The ozone hole formed due to this increase the exposure of direct UV rays on earth carrying the potential risk of skin cancer and other negative effects. Direct exposure of harmful UV rays that penetrates skin can damage the genetic material I.e., DNA in skin cells and if the body is unable to recover the damage the cells stars to divide and grow uncontrollably which eventually leads to a tumour.

The ozone layer is part of the earth's atmosphere. Ozone is basically found in the stratosphere. Ozone layer contains the high concentration of ozone. It's is vital to human life on earth because it absorbs biologically harmful ultraviolet radiations from the sun. Direct exposure to such rays can cause serious illness and skin problems. The main cause of ozone depletion is manufactured chemicals especially CFCs, these compounds reach the stratosphere by winds, where they release halogen atoms through photodissociation and cause the breakdown of ozone into oxygen. The ozone hole formed due to this increase the exposure of direct UV rays on earth carrying the potential risk of skin cancer and other negative effects.