ozone depletion reshma

8/8/2019 Ozone Depletion Reshma

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WHAT IS OZONE LAYER ?

Ozone is a bluish gas that formed bythree atoms of oxygen.The ozone layer is a concentration

of ozone molecule in thestratosphere.The stratosphere reaches 30 miles

above the earth.90% of the planet s ozone is in the

ozone layer.


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IMPORTANCE OF OZONE LAYER

It absorbs 97%-99% of the sunshigh frequency ultraviolet rayswhich are potentially damaging life on earth.Shields the earth from the

harmful effects of UV rays.Ozone layer is known as the

earths umbrella


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OZONE LAYER DEPLETION

It is slow and steadydecline of ozone dueto human activities.


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REASONS FOR DEPLETION

Chlorofluorocarbons are created andused in refrigerators and air

conditioners.These chlorofluorocarbons are not

harmful to humans and have been a

benefit to us.Once released into the atmosphere,chlorofluorocarbons are bombardedand destroyed by ultraviolet rays.

In the process chlorine is released to


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Effects of ozone layer depletion in humans

Skin cancer

Premature aging of the skin

Cataracts and eye disorders

Immune system damage


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E ffects of ozone layer depletion on aquatic life

D ecreasing the abundance of phytoplankton affects the food

stock for fishes and the absorption of CO2D ecreasing the diversity of aquatic

organisms reduces food stock and


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E ffects of ozone layer depletion on land

D amage to plant cell DNA

molecules - makes plants moresusceptible to pathogens and pests

Reductions in photosyntheticcapacity in the plant - results in

slower growth and smaller leaves


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FACTORS

AFFECTING UV

EXPOSUR

E

Clouds cover - partly cloudy days do little toreduce UV exposure but rainy or substantially

overcast days reduce UV exposures

The time of day peak exposure time is 12:00noon - 1:00 p.m. UV intensity is reduced by about

half at three hours before and three hours after thepeak exposure time.


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CONTINU ED .

The time of year - more UV is receivedin the late spring and early summer and

much less is received in the late fall andearly winter.

Life style determines a persons risk

to UV exposure. Skiing, sunbathing, orswimming can lead to extremely highexposures. Use of tanning parlors alsoincrease risk.


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Responses to ozone depletionM ario M olina and Sherwood Rowland

showed in 1974 that CFC gases destroyozoneCoordinating committee on Ozone Layer

(CCOL) established by UNEP in the1970sVienna Convention for the protection of

the ozone layer held in 1985M ontreal Protocol to ban substancesthat deplete the ozone layer held in 1987Amendments to the M ontreal Protocol:

London - 1990, Copenhagen


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MEASURES THAT CAN BE DONE

Encourage afforestationUse of ecofriendly products

Saving energyImpacting lawsPublic awareness


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ozone depletion reshma

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