Ozone Depletion Reshma
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Transcript of 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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