Ozone layer depletion
Ozone is a form of oxygen (O3). In the stratosphere (Ozonosphere),ozone blocks out the sun’s ultraviolet rays and is a life saver.
Ozone as a natural sun block
The electromagnetic radiation emitted from the sun includes ultraviolet radiation, which is potentially harmful to most living things since it can damage DNA. The ozone layer screen out the sun’s harmful ultraviolet radiation. Even 1% reduction in the amount of ozone in the upper stratosphere causes a measurable increase in the ultraviolet radiation that reaches the earth surface. If there was a no ozone at all ,the amount of ultraviolet radiation reaches us would be catastrophically high. All living things would suffer radiation burns,unless they were underground, or in the sea.
In the stratosphere, small amount of ozone are constantly being made by the action of sunlight on oxygen. At the same time, ozone is being broken down by natural processes. The total amount of ozone usually stays constant because its formation and destruction occur at about the same rate. But unfortunately human activity has recently changed that natural balance. Some manufactured substances such as chloroflurocarbons and hydrochloroflurocarbons can destroy stratosphere ozone much faster than it is formed.
Ozone loss was first detected in the stratosphere over the Antarctic. The part of the atmosphere where Ozone is most depleted is referred as ” Ozone hole” but it is not a real hole just a vast region of the upper atmosphere where there is less Ozone than elsewhere.
Ozone-poor air can spread out from the polar regions and move above others areas. In addition, direct Ozone less elsewhere is slowly increasing.
Ozone-poor air can spread out from the polar regions and move above other areas. In addition, direct Ozone depleted area is also slowly increasing.
Reason for Antarctic Ozone hole
Scientific observation prove that the ozone hole formed over Antarctic is due to compounds of chlorine and bromine formed in the atmosphere. Nearly all of the chlorine and half of the bromine in the stratosphere comes from the human activities. The chlorofluorocarbons released due to human activities get transported up into the upper stratosphere.
The most common ozone depleting substances (ODS) are chlorofluorocarbons (CFC) or freon gases,certain bromine compounds, nitrogen oxides and methyl bromide. These compounds are liberally released from air-conditioners,freezers,foam insulation, aerosol products, industrial solvents, fire extinguishers and pesticides.
Effects of ozone depletions
If the ozone is depleted more ultraviolet radiation (especially ultraviolet B (UVB) will reach the earth’s surface.
Effect on plants – will affect crop yield and forest productivity.
Effect on animals – will cause damage to fish larvae and other Small animals.
Effect on human health – results in non – melanoma skin cancer and melanoma ,acute erythemia(sun burn), ocular abnormalities, cataract,poor immune responses.
Preventing ozone depletion
1. CFC’s ( Chloro Fluoro Carbons) should be replaced by HCFC’s (Hydro Chloro Fluro Carbons). If over used could damage ozone, HFC’s ( Hydro Flouro Carbons), Hydrocarbons such as butane and propane ( but flammable and poisonous), Ammonia ( must be handled carefully), water and steam.
2. Production, use and emission of ozone-depleting chemicals should be controlled.
3. Recycling of these chemicals should be increased.
4. Servicing of refrigerators and air-conditioners should be regulated.
5. Refrigerants should be recaptured and used .
6. Adopt protection measures from sun’s radiation.