Ozone Depletion Facts & Information
For the last 450 million years, Earth has natural sunscreen in the stratosphere, called “ozone layer”. Ozone (O3) is a highly reactive gas whose molecules are comprised of three oxygen atoms. Its concentration in the atmosphere naturally fluctuates depending on seasons and latitudes. This layer filters out the harmful ultraviolet radiations from the sun and thus protects various life forms on earth. The theory about the ozone depletion was first started in 1974 by the American scientist, Mario Molina and F Sherwood Rowland. Ozone depletion refers to the thinning of the ozone layer in the stratosphere.
The concentration is greater in the lower stratosphere, (15 to 35 km)and this ozone layer is called good ozone, due to its protective role for living organisms including humans by filtering out about 95% of the harmful radiations. Only10% of ozone found near the ground in the troposphere is a harmful pollutant as a component of urban smog and thus is called bad ozone. In the stratosphere, the formation and destruction of ozone is a combination phenomenon, because the rate of formation is equal to the rate of destruction by natural processes. Man-made chemicals i.e ODS (ozone-depleting substances) are Chlorofluorocarbons,(CFC`S), nitrogen oxides, sulphur dioxide, carbon tetrachloride, Methyl chloroform, chlorine etc. Many of these are being released by flying jets in the stratosphere and rockets being fired into space, but let`s first understand how the emission at the earth surface leads to depletion of the ozone.
The ODS does not react directly with the ozone, first, they get accumulated in the troposphere and then get transported to the stratosphere with the help of natural air motions. Once, in the stratosphere, the ODS is chemically converted to free radicals by UV radiations from the sun. Thus, these radicals react chemically to destroy ozone in the stratosphere. With the depletion of the ozone layer, higher levels of UV radiations reach the earth surface and thus they can be classified as follows –UV-C(100-280), UV-B(280-320) and UV-A(320-390), shorter ultraviolet radiations(UV-C) are absorbed by the atmosphere.UV-B are harmful as well as capable of deep penetration thus the after-effects and consequences of ozone depletion have some ill effects on human health like sunburns, eye cataracts, immune system suppression, skin cancer.
There is a decrease in forest productivity, aquatic species, disrupted food webs, damage to DNA in various life forms, degradation of outdoor paints and plastics, possible climate changes due to accelerated warming. Ozone depletion touched its peak when It led to the ozone hole over Antarctica, We all know that the ozone hole was in news, for a long time but we need to understand how does it occur, the Ozone hole occurs in the region over Antarctica, because Ozone-depleting substances released by humans globally reach the stratosphere from where they are pushed over poles by winds. During winter there is no sunlight and thus the temperature over Antarctica is very low -85 degree celsius. It favours the formation of ice clouds, and these ice clouds provide a catalytic surface where chlorine and other reactants of ODS can react with ozone and degrade it. Ozone hole disappears during summer as warmth mixes up in the Antarctic air with the air of other parts of the world.
The world is helping the ozone to recover as in 1985, countries adopted The Vienna convention, for the protection of the ozone layer, two years later The Montreal Protocol was adopted, till date it has helped to reduce the 97 % of the global consumption and production of ozone-depleting substances. Now the question arises, How can we protect the ozone layer 1. Avoid the consumption of dangerous gases-. Some of the most dangerous gases are CFCs (chlorofluorocarbons), halogenated hydrocarbon, methyl bromide and nitrous oxide, stop their use.
Minimize the use of cars. The best transport option is the urban, bicycle, or walking. If you use a car to a destination, try to carpool with others to decrease the use of cars in order to pollute less and save. Do not use cleaning products that are harmful to the environment and to us. Many cleaning products contain solvents and substances corrosive, but you can replace these dangerous substances with non-toxic products such as vinegar or bicarbonate. Buy local products. In this way, you not only get fresh products but you avoid consuming food that has travelled long distances. As the more distance travelled, the more nitrous oxide is produced due to the medium used to transport that product.
Maintain air conditioners, as their malfunctions cause CFC to escape into the atmosphere. In January 2019, an amendment Aims to slash the use of HFCs by more than 80 per cent 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. We need to protect the ozone from depletion and one day we will, When the world unites and decides to work together, Change will occur.