The document summarizes information about the ozone layer and its depletion. It discusses how the ozone layer protects the Earth from ultraviolet radiation from the sun. It then explains how chlorofluorocarbons (CFCs) were depleting the ozone layer when they were released into the atmosphere. CFCs break down ozone molecules in the stratosphere. The document also outlines observations that show the ozone layer depletion peaked around 2010 and is expected to fully recover by 2065 as CFC use has been restricted by the Montreal Protocol.

1. THE OZONE LAYER AND ITS
DEPLETION
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2. THE OZONE LAYER
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3. INDEX
TOPIC Pg no.
Layers of the Atmosphere 4-5
The Sun’s Utraviolet Rays 6-8
The Ozone Layer 9
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4. LAYERS OF THE ATMOSPHERE
The atmosphere is divided into five layers. It is thickest
near the surface and thins out with height until it
eventually merges with space.
1) The troposphere is the first layer above the surface and
contains half of the Earth's atmosphere. Weather occurs in
this layer.
2) Many jet aircrafts fly in the stratosphere because it is
very stable. Also, the ozone layer absorbs harmful rays
from the Sun.
3) Meteors or rock fragments burn up in the mesosphere.
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5. 4) The thermosphere is a layer with
auroras. It is also where the space
shuttle orbits.
5) The atmosphere merges into space in
the extremely thin exosphere. This is
the upper limit of our atmosphere.
Ozone layer
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6. THE SUN’S ULTRAVIOLET RAYS
The sun emits energy over a broad spectrum of
wavelengths:
visible light that you see
infrared radiation that you feel as heat
ultraviolet (UV) radiation that you can’t see or feel.
UV radiation has a shorter wavelength and higher
energy than visible light.
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7. It affects human health both positively and
negatively.
Short exposure to UVB radiation generates vitamin
D, but can also lead to sunburn depending on an
individual’s skin type.
Fortunately for life on Earth, our atmosphere’s
stratospheric ozone layer shields us from most UV
radiation
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8. Damage to the ozone layer can cause the following:
Skin cancer
Cataracts
Suppression of the immune system
Premature aging of the skin
Since the benefits of sunlight cannot be separated
from its damaging effects, it is important to
understand the risks of overexposure, and take
simple precautions to protect yourself.
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9. THE OZONE LAYER
The ozone layer is a deep layer in the
stratosphere, encircling the Earth,
that has large amounts of ozone in it.
The layer shields the entire Earth
from much of the harmful ultraviolet
radiation that comes from the sun.
For nearly a billion years, ozone
molecules in the atmosphere have
protected life on Earth from the
effects of ultraviolet rays.
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10. THE OZONE LAYER DEPLETION
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11. INDEX
TOPIC Pg no.
The Ozone Hole and Its Causes 12-13
Observations on Ozone Layer 14
Depletion
Observation 1 15
Observation 2 17
Misconceptions about the Ozone Layer 18
Depletion
Bibliography 19
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12. THE OZONE HOLE AND ITS CAUSES
Recently, chlorofluorocarbons (CFCs) were used a lot
in industry and elsewhere to keep things cold and to
make foam and soaps.
Strong winds carry CFCs up into the stratosphere
where UV radiation breaks them apart, releasing
chlorine atoms.
Each chlorine atom can attack and break apart
(destroy) as many as 100,000 ozone molecules during
the time it is in the stratosphere.
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13. The chlorine from CFCs reduces (depletes) the amount of
ozone in the stratosphere.
Other ozone-eating chemicals are pesticides such as methyl
bromide, halons used in fire extinguishers, and methyl
chloroform used in businesses.
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14. OBSERVATIONS ON OZONE LAYER
DEPLETION
There are many observations
on the ozone layer. The
following are a few
observations:
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15. OBSERVATION 1
Scientists did predict that ozone depletion should
peak around year 2010.
As world-wide controls reduce the release of CFCs
and other ozone-eating substances, nature will repair
the ozone layer.
By year 2065 stratospheric ozone should return to the
amount present in 1980.
Until then, we can expect higher levels of UV
radiation at the Earth's surface.
We need to take care to avoid the bad health effects
that could result from too much UV radiation.
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16. 16

17. OBSERVATION 2
Most countries have seen the threats created by
ozone depletion and agreed to a treaty called the
Montreal Protocol.
This Protocol will help humans to stop making and
using ozone-eating chemicals.
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18. MISCONCEPTIONS ABOUT THE
OZONE LAYER DEPLETION
COMMON MISTAKE FACT
Global warming is caused The ozone layer protects the
by the ozone hole which Earth from the Sun’s harmful
UV rays. Hole in the ozone
was created by chemicals
layer has been caused by
like CFC etc. chemicals released by humans.
CFC’s are “too heavy” to CFC’s are commonly believed
reach the stratosphere. to be heavy. But atmosphere
gases are not sorted by
weight. The wind mixes the
gases and they reach the
18 atmosphere.

19. PROTECTING THE OZONE LAYER
The ozone layer must be protected.
For this the use of CFC’s has to be stopped.
We must buy products that are labelled “ozone
friendly” or “ CFC free”.
Substitutes for CFC’s should be used.
HCFC’s are substitutes for CFC’s.
Let us all take a step ahead and save the ozone layer.
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20. BIBLIOGRAPHY
http://epa.gov/sunwise1/kids/kids_ozone.html
http://www.epa.gov/sunwise/doc/uvradiation.html
http://en.wikipedia.org/wiki/Ozone_depletion
http://www.windows2universe.org/earth/Atmosphere
/layers.html
http://www.google.com/imgres?q=ozone+layer&hl=e
n&biw=1360&bih=649&gbv=2&tbm=isch&tbnid=U_EY
VGK2GX8xbM:&imgrefurl=http://www.okiu.ac.jp/Lang
uage/contest/02/12/ozone.htm&docid=M7
http://www.theozonehole.com/ozoneholehistory.htm
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21. MADE BY:
AAKANKSHA MADAN
SHREYA SINGH
NIDA MEMON
RIYAA SOMANI
SAAMIYA SIDDIQUI
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