Fallout of ozone depletion

The world needs serious awareness of the fallout of ozone depletion in the atmosphere. September 16 being the International Ozone Day (IOD), scientists and nature lovers around the world get together to explore and explain about ozone depletion and other consequences of allowing environmental degradations to harm the earth.

Here in India, most of us are hardly aware of the consequences of ozone depletion in the atmosphere. Even our political leaders and bureaucrats today feel that such issues are not really a priority for India. This madness was amply demonstrated when India did not clearly spell out its position on the issue of hydrofluorocarbons (HFCs) during  a key UN conference in Paris (France) recently, when nations debated whether to set up a contact group for discussing the proposed amendment to the Montreal Protocol to phase down the harmful greenhouse gas.

Experts point out that between ozone depletion and climate change, the very ecological and food security of the Indian sub-continent could be at grave risk. Soils could go sterile and extinction of vulnerable species could become a reality. It is really sad that ignorance and apathy continues to rule the roost in India's decision-making process. 

According to experts, Ozone is a form of oxygen that is present in the Earth's atmosphere in small amounts. Ozone in the upper atmosphere is a major factor in making life on earth possible. But ozone in the lower atmosphere contributes to air pollution.

Ozone is produced naturally through photo-chemical and electric discharge reactions. Photochemical production occurs when high energy radiation from the Sun strikes ordinary oxygen in the earth's upper atmosphere and converts some of it to ozone. Electric discharge reactions including lightning and electric sparks from motors, also convert some oxygen to ozone.

Most ozone is found in the upper atmosphere. The highest concentration is reached, depending on the latitudes, between about 15 and 50 kilometres above the earth's surface. This concentration is 10 parts per one million by volume - that is, 10 parts of ozone per one million parts air. The ozone layer in the upper atmosphere shields the earth from 55 to 90 per cent of the Sun's ultraviolet (UV) rays. Over exposure to these rays, is a leading cause of skin cancer and other skin infections.

In the mid I970s, some scientists expressed concern that chemical compounds called chlorofluorocarbons (CFCs) were breaking down the protective ozone layer. At that time, CFCs were widely used as propellants in aerosol sprays cans. After CFCs are released, they slowly rise into the atmosphere. When they reach the upper atmosphere, the Sun's ultraviolet radiation breaks them apart. Some of the molecular fragments that result, react with ozone, thereby reducing the amount of it.

Scientists have discovered that the decrease of ozone in the upper atmosphere depends on the latitudes. The decrease is the strongest in regions over the South Pole, where it forms a "hole". Scientists from the British Antarctic Survey published the first report of the existence of an ozone hole above the Hailey Bay in I935. In 1936, NASA, together with such organisations as the World Meteorological Organization and the United Nations Environmental Programmes (UNEP), set up the Ozone Trend Panel (OTP) to study ozone depletion in the atmosphere. Members of this panel collected data from satellites and from instruments on the ground. They published their findings in March 1938, confirming that the ozone levels above the Antarctic were indeed decreasing. They also found that ozone levels were decreasing in Arctic regions, but to a lesser degree than the formation of the ozone hole above the Antarctic. In 1987, 31 nations signed the Montreal Protocol, a treaty to limit the production of CFGs. This treaty took effect on January I, 1989. In 1990, a re-evaluation of the Montreal Protocol established that the worldwide increase in production of CFCs had slowed down. But it was found that some of the compounds introduced to replace CFCs were also harmful to the ozone layer, especially hydrochlorofluorocarbons (HCFCs). A revision of the Montreal Protocol of 1990 calls for the complete elimination of the production of CFCs by the turn of the century.

According to experts, CFCs will contaminate the atmosphere for many years after the production of CFCs end. This is because large amounts of CFCs from existing refrigerators and air-conditioning systems are leaking into the atmosphere. Also, scientists expect that ozone depletion will continue to increase over the next few decades because CFCs are long-lived molecules. The consequence of ozone depletion will be an increase in the amount of ultraviolet light that reaches the earth, especially in the Southern regions of the globe.

Most ozone in the lower atmosphere is considered an air pollutant. Exposure to certain concentrations causes headaches, burning of eyes and irritation of the respiratory tract.

Ozone is used as an oxidant in certain chemical process: to bleach oils, fats and textiles, and to eliminate harmful compounds in industrial wastes.

 India was involved in monitoring atmospheric ozone as far back as 1926 (during foreign colonial rule) when Dr. Royds took total ozone measurements in Kodaikanal using what was called the Dobson's photoelectric Ozone Spectrograph. We were then at the forefront of science as these were amongst the first worldwide ozone measurements that had been organized by Prof. G.M.B. Dobson. Unfortunately, today that scientific temper, the curiosity, the humility to know that nature is to be understood, not abused; seem totally lacking.

It is very important that we immediately phase out the manufacture and use of ozone depleting substances and find alternative for 3 their use. Make sure the ordinary products we use at home, do not contain ozone depleting substances. It is necessary to educate our children to grow up to be better prepared to deal with the environment problems we have created for ourselves.

(The writer is a 

freelance journalist)