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Ozone paradox Despite its irritating effects on humans in high concentration, Ozone has
found enormous application in industry in a controlled quantity Trends Too late to contain killer flu science: scientists Prof Yash
Pal THIS UNIVERSE |
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Ozone paradox IN the air pollution abatement, Ozone does represent an amazing paradox, exhibiting an apparently contradictory nature. An ordinary but awaken person has popular misinformation that ozone is toxic in air, a real health hazard and major pollutant to be avoided. When people think of air pollution, they often think of ozone levels and intermix the two directly. So, the idea of ozone gas as air purifier becomes an apparent contradiction. But the contradiction is only “apparent”, for there is in practise no safer, effective and super convenient oxidising agent to purify the polluted air than this very natural gas. Ozone is a molecule of three oxygen atoms formed from naturally occurring stable oxygen molecules by association of an extra oxygen atom in air. The result is a relatively unstable molecule that is anxiously willing to depart that third atom of oxygen to other substances. This alone property of ozone makes it a powerful oxidising agent. In environmental technology, Ozone has been approved as a strong cleaning, purifying and oxidising agent which reacts with organic molecules and substances to remove unpleasant odours, neutralise toxic volatile compounds, remove flora and fauna of ecology, soothe climatic change and kill germs. Pardoxically, this oxidation potential is its strength and at the same time its weakness, too. It represents both the challenge and opportunity if we analyse its ethics qualitatively and quantitatively. Despite its irritating effects on humans in high concentration, Ozone has found enormous application in industry in a controlled quantity. It is good at high (in ozonosphere that protect us from UV radiations) but bad nearby in high concentration. In a controlled quantity, Ozone is used for water purification, whitening of textile clothes and as disinfectant. The Indian Council of Food and Drug, as per recent approval from the US Food and Drug Administration (FDA), has recommended ozone in low concentration to sterilise food and food-contact surfaces. Just as Ozone cleans outdoor air as its natural phenomenon, it has tremendous potential for improving indoor air quality under right conditions. Pure ozone is produced naturally and has pale blue colour, when it is isolated as a crystalline solid or liquid at very low temperatures. Ozone is a colourless gas. However, due to thick layers in ozonosphere and otherwise, too, it appears as a blue clean sky. When it is generated commercially from air, a colourless gas is produced. At low concentration in part per billion concentrations (one part in 109 litres of air), it has a very distinct sweet and pleasant odour like the fresh air after a heavy rain and thunderstorm due to lightning discharge effect. People compare it to the smell of spring. A protective layer of ozone is present in the region 16 to 30 km above the earth’s surface at a concentration of 1-10 ppm (parts per million). This is referred as stratosphere that performs the indispensable function of absorbing harmful UV radiations to shield the biosphere. To the environmentalists, this ozone layer has a deep concern and the effects of either increasing it to create the “green house effect” or else depleting it to let more UV to cause increased incidence of skin cancer, eye cataract and diminishes crops yield. So, both situations must be avoided at all costs. Natural ozone concentrations at ground level can vary between 10 ppb to 50 ppb depending upon the geographic location, altitude, local weather and its ambient conditions. It is formed spontaneously by the actions of the sun’s UV radiations on the copious oxygen component of the atmosphere, with which it forms a stable but dynamic equilibrium. An ozone molecule is stable with a half-life of about 21 minutes. So, it is continuously being produced and then it reverts back to the more stable oxygen molecule. As a powerful oxidising and sterilising agent, ozone also decomposes to a non-toxic environmentally safe product. At ground level, as a natural discourse, ozone is formed due to photosynthesis of nitrous oxide gas released from automobiles exhaust; industrial effluents, mass fuel burners, ultraviolet radiation from sun, thunderstorm and lightning discharge, photocopier machine, arc welding, sterilisation and decay of potassium nitrate in the agricultural fields during the post-harvesting season. Due to above facts, when ozone concentration exceeds the permissible level, it triggers a variety of health problems, including chest pain, coughing, nausea, throat irritation and congestion. Ozone can inflame and damage lung cells. It can also aggravate chronic lung diseases like emphysema and reduce the immune system’s ability to fight off bacterial infections in the respiratory system. According to the United States Environmental Protection Agencies (EPA), below 64 ppb (parts per billion) level of ozone has been considered to be generally safe and time weighted average of 8 hours exposure for industrial workers has been fixed to be 100 ppb. As per the EPA, the air quality index above 85 ppb ozone concentration (purple—colour code) has been taken as unhealthy air. Excess of anything is bad and so is with ozone, too. When used properly and safely, obtainable from either natural resources or electronic ozone generator (instrument), ozone technology can be an inexpensive and effective tool for eliminating many unwanted odours and pollutants present in indoor air, excluding agriculture, water treatment, fish canneries, food sanitation, industrial waste, therapeutic use, as an excellent disinfectant of pools and spas. Ozone has gained FDA approval as a sanitiser not only for food contact surfaces but also for direct application on food against bacteria, fungi, viruses, protozoa bacterial and fungal spores because it brings genetic changes under cell lysing process, which the chlorine cannot. Ozone is essentially safe in almost all normal situations and practical applications. The ozone layer surrounding the earth’s surface is ozonosphere, extending to the stratosphere region. It protects biosphere from sun’s harmful ultraviolet rays (UV-B). The effects of UV-B are apparent particularly in India and Asia-Pacific and growth of red pigments on outer body skin has been observed mostly in Australia (Sydney, Melbourne and Perth). This is mainly due to ozone depletion and thereafter formation of ozone hole over the continents. So, again ozone is blissful at height. The Central Scientific Instruments Organisation (CSIO), Chandigarh, in collaboration with the Department of Environment, Chandigarh, has developed a real-time ozone monitor. The ozone concentration level of Chandigarh has been monitored at ground level and it has been found maximum near the Aroma light point between 7 am and 11 am during winters. A survey report conducted by Indian environmentalists reveals that during summer, the ozone layer at Kodai Kanal, Delhi and Srinagar deplete to the tune of 2,80,270 and 360 Dobson units, which bring a bad regional effect. India’s Central Pollution Control Board through state pollution control boards has been empowered by the Ministry of Environment and Forests to implement regulations relating to control and monitoring production and consumptions of ozone depleting substances. India has been following a structured approach in achieving its targets relating to the Montreal Protocol to protect ozone layer depletion and infilling the ozone hole. The stratospheric ozone layer should heal through reduced emission of ozone depleting substances. However, due to the long lifespan of these chemicals and their gradual migration to stratosphere, we have yet to face the time of grater solar radiation levels and the potential consequences. Ozone technology is indeed a blissful technology and techno economical solution from the ground to upper atmosphere. In the application of any technology, risk benefit analysis must be prepared. Under such evidences, the ozone is never the paradox. With careful consideration, the net balance in favour cautions ozone use and protecting ozone depletion for any proven application is eminently obvious. It is the rational choice both commercially and domestically. A little truth mixed with a little ignorance sometimes offers lot of ignorance. So, we should recognise the ozone as a life-saving molecule. The writer is a former scientist, CSIO, Chandigarh
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Trends BAIKONUR: A trio of astronauts blasted off aboard a Russian Soyuz rocket on a mission to bring the International Space Station back up to full manpower after an August cargo launch accident disrupted flights. The rocket carrying Russian cosmonaut Oleg Kononenko, NASA astronaut Don Pettit and the European Space Agency's Andre Kuipers lifted off at 8:16 a.m. EST on Wednesday under freezing conditions at the Baikonur Cosmodrome in Kazakhstan, a NASA Television broadcast showed. The all-veteran crew is scheduled to reach the orbital outpost at 10:22 a.m. EST on Friday. They will join station commander Dan Burbank and two Russian cosmonauts who arrived last month, bringing the complex back to its full live-aboard staff of six. — Reuters
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Too late to contain killer flu science: scientists ATTEMPTS to suppress details of the controversial experiments that have created a highly infectious form of bird flu virus are likely to fail, according to scientists familiar with the research. The US government has asked two scientific journals to refrain from publishing key parts of research on the H5N1 strain of bird flu to prevent the information falling into the hands of terrorists intent on recreating the same flu strain for use as a bioweapon. However, scientists say the plea comes too late because the information has already been shared widely among flu researchers. Others argue that the move could obstruct attempts to find new vaccines and drugs to combat an infectious form of human H5N1 if it appeared naturally. — The Independent
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THIS UNIVERSE How does a ring form around the crescent moon? How do we see the dark part of the moon even when no direct sunlight reaches? When you have a crescent moon, a large part of the moon that could be seen by us is not illuminated by the sun. But it is facing the illuminated portions of the earth. As a result, the dark part of the moon is seen because of the faint light from the illuminated part of the earth-the earthshine on the moon. An atmosphere on the moon is not required. Readers wanting to ask Prof Yash Pal a question can e-mail him at palyash.pal@gmail.com
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IN the air pollution abatement, Ozone does represent an amazing paradox, exhibiting an apparently contradictory nature. An ordinary but awaken person has popular misinformation that ozone is toxic in air, a real health hazard and major pollutant to be avoided. When people think of air pollution, they often think of ozone levels and intermix the two directly.
