Ozone depletion is allowing the UV radiation to earth surface. The exposure to these radiations is severely affecting all life forms on earth, especially the humans. Permanent or temporary blindness, skin cancer and immunity suppression are the main effects of these radiations reported by various researchers on humans.
The prospects of ozone recovery are still undiscovered. The current situation of ozone depiction demands urgent remedial measures to protect lives on this earth. Many of human activities are badly affecting the atmosphere. Ozone depletion is one of those examples [1]. Life is protected from UV rays by stratospheric ozone layer which acts as a shield or sun screen [2].
Ozone O 3 is colourless just like oxygen O 2 but it has very harsh odour. It is very rare as compared to oxygen. It is estimated that out of 10 million air molecules about 2 millions are of O 2 and only 3 are of ozone [5]. The process of ozone formation is called as photolysis. When the UV radiations from sun strike the O 2 molecules, it causes splitting of O 2.
Oxygen molecules react with oxygen atoms in the upper atmosphere to form ozone. U [1]. Normal ozone concentration is between - D. U [5]. In our present study, we shall discuss how ozone layer depletion is affecting human health and we shall also discuss some recommendations to minimize ozone depletion and its adverse effects on human health.
The ozone layer is basically naturally occurring gas in the region of stratosphere where ozone particles are accumulated [2]. Ozone layer is also naturally broken down but there is a balance between its formation and natural depletion.
As a result the total amount of ozone remains constant. But ozone layer thickness varies with altitude and seasonal change. Ozone concentration is highest between 19 - 23 km [6]. Most of ozone is formed at equator where there is maximum sunshine but with winds it travels at high altitude and get accumulated in stratosphere [1]. Ozone hole is created in the region where ozone layer has been depleted. Ozone holes are first discovered in Antarctica in Few years ago ozone holes are also discovered in arctic region.
Since rate of ozone depletion is increasing 0. Due to depletion of Ozone UV rays are penetrating in troposphere and leading to more ozone formation in troposphere which is causing injurious effects on our health as ozone is toxic for our body [8]. Ozone depletion occurs when the natural balance between the production and destruction of stratospheric ozone is disturbed. Although natural phenomenon can cause ozone depletion but human activities such as CFCs are now accepted as major cause of depletion [9].
All ozone depleting chemicals contain chlorine and bromine [10]. CFCs are highly volatile and non combustible so they are very quickly evaporated and can easily reach in stratosphere where ozone is present here they start depleting ozone molecules. These CFCs have also adverse affects on human health [11].
According to the chemical model for ozone destruction proposed about 20 years ago, the photolysis of Cl 2 O 2 is key to ozone depletion reaction. But now atmospheric researchers studied that the rate of this reaction is not extremely high as it was thought previously so we can no longer say that CFCs are the main cause of ozone depletion [12].
Another major cause of large scale ozone depletion is Rocket launches. It has been studied that unregulated rocket launches can result in much more ozone depletion than CFCs. It is estimated that if rocket launches will be let unregulated then it would cause huge ozone loss by the year than the CFCs have done [1]. Global warming also leads to ozone layer depletion.
Due to global warming and green house effect most of the heat is trapped in troposphere which is the layer below the stratosphere. Nitrogenous Compounds emitted by human activities in small amount like NO, N 2 O and NO 2 are considered to be greatly responsible for the depletion of ozone layer [13].
Ozone depletion is affecting the human health and environment negatively, as it allows the penetration of UV radiations to reach the Earth. These radiations can cause severe diseases in humans such as skin cancer, eye damage and genetic mutations etc.
Furthermore the ozone depletion is affecting the aquatic life, biogeochemical cycles, air quality and also contributing in Global warming but in this review paper our main focus is on the effects of ozone depletion on human health [1]. The major cause of blindness in this world is cataracts. There would be 0. Eye lens can be damaged by oxidative agents. Oxidative oxygen produced by UV radiation can severely damage eye lens and cornea of eye is also badly damaged by UV radiation [15] -[17].
Photokeratitis, cataract, blindness all are caused due to UV rays [18]. Exposure to UV radiations can cause skin cancer. UV radiations alter the structure of biomolecules and thus lead to different diseases [10] [19] Skin is the most often exposed part of body to UV radiations There are two types of skin cancer, Melanoma and Non-melanoma. Melanoma is most serious form of cancer and is often fatal, while non-melanoma is most common type and less fatal.
Depletion of ozone layer leads to both Sun burn and skin cancer [20]. UV radiations are also responsible for breast cancer and leukemia [18]. Epidemiological studies of Melanoma indicate that the incidence of melanoma is increasing in those countries having high ratio of cases [21] - [23]. As UV radiations can penetrate more easily in thin skin so there is greater number of incidence is found in thin skinned people. It is found that the incidence of Melanoma is more in children than adults.
The chance of incidence of melanoma is correlated with UV exposure furthermore the survival chance of melanoma is less in boys as compared to girls [24] [25]. It is a cause of melanoma and other types of skin cancer. It has also been linked to damage to some materials, crops, and marine organisms.
The ozone layer protects the Earth against most UVB coming from the sun. It is always important to protect oneself against UVB, even in the absence of ozone depletion, by wearing hats, sunglasses, and sunscreen. However, these precautions will become more important as ozone depletion worsens.
Studies have shown that in the Antarctic, the amount of UVB measured at the surface can double during the annual ozone hole. Addressing Ozone Layer Depletion. Laboratory and epidemiological studies demonstrate that UVB causes non-melanoma skin cancer and plays a major role in malignant melanoma development.
Source: Figure Q from Michaela I. Hegglin Lead Author , David W. Montzka, and Eric R. Because all sunlight contains some UVB, even with normal stratospheric ozone levels, it is always important to protect your skin and eyes from the sun. See a more detailed explanation of health effects linked to UVB exposure.
EPA uses the Atmospheric and Health Effects Framework model to estimate the health benefits of stronger ozone layer protection under the Montreal Protocol. Spring brings sunlight, which releases chlorine into the stratospheric clouds. Recognition of the harmful effects of CFCs and other ozone-depleting substances led to the Montreal Protocol on Substances That Deplete the Ozone Layer in , a landmark agreement to phase out those substances that has been ratified by all UN member countries.
Without the pact, the U. More than 30 years after the Montreal Protocol, NASA scientists documented the first direct proof that Antarctic ozone is recovering because of the CFC phase-down: Ozone depletion in the region has declined 20 percent since And at the end of , the United Nations confirmed in a scientific assessment that the ozone layer is recovering, projecting that it would heal completely in the non-polar Northern Hemisphere by the s, followed by the Southern Hemisphere in the s and polar regions by A study in early found that ozone in the lower stratosphere unexpectedly and inexplicably has dropped since , while another pointed to possible ongoing violations of the Montreal pact.
The world is not yet in the clear when it comes to harmful gases from coolants. Some hydrochlorofluorocarbons HCFCs , transitional substitutes that are less damaging but still harmful to ozone, are still in use.
Developing countries need funding from the Montreal Protocol's Multilateral Fund to eliminate the most widely used of these, the refrigerant R The next generation of coolants, hydrofluorocarbons HFCs , do not deplete ozone, but they are powerful greenhouse gases that trap heat, contributing to climate change.
Though HFCs represent a small fraction of emissions compared with carbon dioxide and other greenhouse gases , their planet-warming effect prompted an addition to the Montreal Protocol, the Kigali Amendment , in The amendment, which came into force in January , aims to slash the use of HFCs by more than 80 percent over the next three decades.
In the meantime, companies and scientists are working on climate-friendly alternatives, including new coolants and technologies that reduce or eliminate dependence on chemicals. All rights reserved. Climate Ozone Depletion The ozone layer helps to protect life from harmful ultraviolet radiation.
Find out what caused the ozone hole, and how the Montreal Protocol sought to put an end to ozone depletion. Ozone threats and 'the hole' In , Mario Molina and Sherwood Rowland , two chemists at the University of California, Irvine, published an article in Nature detailing threats to the ozone layer from chlorofluorocarbon CFC gases.
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