Ozone Day

World Ozone Day

Ozone is composed of three oxygen atoms, and it is unstable. That form a fragile layer shield and forms a life given layer of poison. It is naturally present in our atmosphere.

• Ozone is found in varying concentration from earth surface at height of 50 Km.
• The lower layer of stratosphere is known as Ozone Sphere, Ozone Layer or Protective layer of Ozone or Ozone umbrella.
• The Montreal Protocol was originally signed on 16^th September 1987 the day is celebrated as Ozone Day.

The benefits of fragile shield Ozone layer: –

The fragile thinnest layer of ozone filter and effectively screen all most harmful UV radiation from sun.

Fig. 1 Schematic view of ozone layer []

 UV (ultra-violet) radiation (400-200nm) are 3 types-

• UVa 400-315nm harmless allow and almost entirely allow through layer
• UVb 315-280nm harmful and almost absorbed by the layer
• UVc 280-200nm lethal to living being and completely absorbed by the layer

 Ozone plays two very different roles in Global Environment Change

• Ozone is the stratosphere absorbs some of the sun’s biologically harmful ultraviolet radiation. Because of this beneficial role, stratospheric ozone is considered “Good Ozone”.

Ozone Depletion: –

Ozone depletion is not nothing but a dramatic thinning of ozone layer in the stratosphere. It is not a permanent phenomenon it is a seasonal phenomenon.

Sources of ozone depletion:-

• High altitude
• Chlorofluorocarbons (CFC’s) which are widely used as aerosol spray propellent, refrigeration, fire extinguisher
• Nitrogen oxide produced by action of bacteria and use of nitrogenous fertilizer in agricultural activities.
• Huge buildup of gas and chemicals emitted by industrial plants and automobiles.

Ozone depleting substances (ODS)

• Chlorofluorocarbons (CFCs)
• Hydrochlorofluorocarbons (HCFCs)
• Chloroforms (CHCL3)
• Halons

Consequences of ozone depletion: –

The penetration of UV-B radiations through the atmosphere, due to ozone depletion, has the following implications.

• Human health: – UVb radiations are sufficiently energetic to break biological molecules including protein and DNA.
• Skin: – exposure to UV-b radiations cause the connective tissue of the skin to damage as a result, the skin becomes finely wrinkled and loss its elasticity.
• Eyes: – eyes are to excessive UV-b exposure the ocular pigment cells which normally sharpen our sight by reducing reflect light inside the eye can malfunction when exposed to UV rays Melanoma of eyes, blindness can occur.
• Crop yields: – A 1 % increase in UV-B rays is estimated to cause 1% decline in the field of Soya beans and peas.
• Global warming: –due to harmful UV radiation the globally atmospheric temperature is annually rising because they(uv rays) trap the trap the heat waves and cause global warming which has later on impacts on glaciers melting.