Ozone layer is a region of the stratosphere, between 15 and 30 kilometres in altitude, containing a relatively high concentration of ozone. The layer is of two types namely bad ozone, formed in the lower atmosphere called Troposphere and the good ozone found in the upper part of the atmosphere called the Stratosphere. As the name suggests, bad ozone harms plants and animals whereas the good one acts as a shield absorbing UV Ultraviolet) radiations coming from the sun. Ultraviolet radiations are radiations that are detrimental to our skin and eyes. On exposure, the bonds of DNA and protein present in our skin are broken by the harmful radiations of the sun thereby causing damage to the skin. These rays are of different wavelengths and depending on these wavelengths the damage is caused. The rays with wavelength shorter than UV-B cause no harm whereas UV-B cause mutation and damage to skin such as skin ageing injure skin cells and induce skin cancers. In case the human eyes are exposed to these rays, it leads to swelling of the cornea called snow blindness. The affect doesn’t only remains confined to humans but also to plants. UV-B diminishes photosynthesis and damages very useful nucleic acids.
Since ages the ozone shield has been protecting us from these radiations. They act as a screen over the atmosphere and don’t allow UV radiations to reach us. This task of protection works on the principle of the balance maintained between the production and degradation of ozone in the upper layer of the atmosphere. Ozone gas is produced as a result of the action of UV rays on molecular oxygen and degrades into the same molecule of oxygen.
But of late, the balance has been disturbed due to increased usage of products harmful to the ozone layer. Some of these products are Chlorofluorocarbons (CFCs), DDT sprays and Aerosol sprays. CFCs are used in refrigerators as major refrigerants. CFCs on discharge move to the stratosphere from the lower layer. Thus, they enhance the degradation of the ozone gas thereby disrupting the balance. In the upper atmosphere when the CFCs are acted upon by the Ultraviolet rays, chlorine molecules are released. These molecules act on the molecular oxygen that release ozone. So far, ozone depletion has occurred in the Stratosphere but a major part of it is present over Antarctica. Such ozone depletion is called an Ozone Hole. The hole above Antarctica forms mainly between late August and early October. The major reasons for such deleterious effects on ozone are mainly CFCs and other ozone depleting chemicals such as DDT. Moreover, DDT also enhances Biomagnifications. High concentration of DDT leads to lack of calcium among birds which causes premature breaking of the egg shells thereby causing reduction in the bird population.
The increase in the ultraviolet radiations is also giving way to global warming due to the increased temperature and the blanket formed by harmful gases and chemicals such as CFCs, carbon dioxide and methane along with sprays that contain aerosols. This blanket doesn’t allow excess heat (infrared radiations) to escape from the earth’s surface. This alters the normal patterns of nature and the overall disruption of food production.
The toxicity of ozone majorily causes mutation. Mutation will increase vulnerability to cancer causing agents called Carcinogens and will lead to a problem that can last for an unexpected period of time. On one hand we oppose the method of disposal of nuclear waste so as to avoid the factors that might lead to cancer, while on the other, the above mentioned reasons for ozone depletion are heading towards the same problem.
It’s high time that we avoid chemicals that can create troubles for our future and use eco friendly methods to go hand in hand with technology. Ozone depletion is a non-reversible phenomenon it cannot be replaced anyhow. Thus it is very important to take numerous steps which can help us overcome the problem of depletion.
The 1989 Montreal Protocol was signed to control and reduce the emissions of CFCs and other ozone diminishing elements. The refrigerators are now being made CFCs free.
The production of CFCs has been banned since 1996. The recent G8 summit and Kyoto Protocol deal with measures to safeguard the environment. According to both the agreements, developed or developing countries that make much use of technology are instructed to reduce the gas emissions. By far the U.S.A has topped the list of pollution causing countries. Thus it is important for such countries to take steps to combat the much hyped problem.
It is important to realize that long gone ice and heat ages are not far away. We are reaching such ages at an alarming rate. As it is said, “Better late than never”. Our future is in our hands and it depends on us to make it secure and to conserve what all we can for the future generation.