The document discusses the ozone layer, its importance in shielding the Earth from UV radiation, and the threats to it. It notes that ozone is found mainly in the stratosphere, where it forms the ozone layer between 6-30 miles above the surface. The ozone layer absorbs most of the sun's UV rays and plays a key role in atmospheric temperature. However, chlorofluorocarbons and other ozone-depleting substances have damaged the ozone layer, leading to the Antarctic ozone hole. This depletion increases UV levels and can harm both human health and the environment. International agreements like the Montreal Protocol have sought to phase out ozone-harming chemicals and find alternatives.

5.  A molecule containing three atoms of
oxygen is called ozone.
 Ozone is very rare in our atmosphere,
averaging about three molecules of ozone for
every 10 million air molecules.
 ozone plays a vital role in the atmosphere. It
shields the entire Earth from much of the
harmful UV radiation that comes from the sun.
OZONE

6.  Ozone is mainly found in two regions of the
Earth's atmosphere.
Most ozone (about 90%) resides in a layer that
begins between 6 and 10 miles (10 and 17
kilometers) above the Earth's surface and
extends up to about 30 miles (50 kilometers).
 This region of the atmosphere is called the
stratosphere. The ozone in this region is
commonly known as the ozone layer.

7. •,
• The ozone layer is mainly found in the lower
portion of the stratosphere.
• It contains high concentrations of ozone(O3)
relative to other parts of the atmosphere.
• The ozone layer was discovered in 1913 by the
French physicists Charles Fabry and Henri
Buisson.
• The ozone layer refers to a region of Earth's
stratosphere that absorbs most of the Sun's
UV-radiation.

8.  The earth's atmosphere is divided into several
layers, and each layer plays an important role. The
first region extending about 10km upwards from
the earth's surface is called the troposphere.
Many human activities like mountain climbing,
gas balloons and smaller aircrafts operate within
this region.
The next layer, extending about 10-50 km is
called the stratosphere .where the ozone layer
(lower portion)found, though the thickness varies
seasonally and geographically.

10. UV- radiation
• Ultraviolet (UV) light is an electro magnetic
radiation with a wavelength from 400 nm to
100 nm.
• UV are of 3 types UVA,UVB,UVC.
• UVA is not harmful as UVB (315-400nm),UVB
decreases atmospheric ozone cause biological
damages(280-315nm),UVC get absorbed by
ozone(200-280nm)

11.  The absorption of ultraviolet radiation by
ozone creates a source of heat.
Ozone thus plays a key role in the
temperature structure of the Earth's
atmosphere.
Without the filtering action of the ozone
layer, more of the Sun's UV radiation would
penetrate the atmosphere and would reach
the Earth's surface.
 The harmful effects of excessive exposure to
UV radiation .It causes harmful effect to crop,
forest growth and human health.

12. • Some parts of Antarctica, up to 60% of
the total overhead amount of ozone
(known as the column ozone) is depleted
during Antarctic spring (September-
November).
• This phenomenon is known as the
Antarctic ozone hole.
• In the Arctic polar regions, similar
processes occur that have also led to the
depletion of column ozone.

14. The term "ozone depletion" means more than just the
natural destruction of ozone
Damage in the ozone layer will naturally mean
the entry of harmful rays in to the atmosphere.
Or Decrease in stratospheric ozone around
earth’s polar region this phenomena is referred
as ozone hole.

15. The Antarctic Ozone
Hole

17. Damage to the ozone layer can cause
the following
For human
• Skin cancer
• Cataracts
• Suppression of the immune system
• Premature aging of the skin

18. Effects on the Environment
• Global warming
• Climate change
• Crop and forest damage
• Infections and skin diseases on animals
• Less fish harvest

19. The Ozone hole as
seen from the Earth

20. • The primary cause of ozone depletion is the
presence of chlorine-containing source gases
(primarily CFCs and related halocarbons).

21. Ozone layer is being destroyed by a group of
manufactured chemicals that are called ODS or
Ozone-Depleting Substances
Chlorofluorocarbons
Methyl bromide (CH3Br)
Carbon tetrachloride (CCI4)
-Depleting Substances

22. A chlorofluorocarbon (CFC) is an organic
compound that contains only carbon, chlorine,
and fluorine .Since the 1930s in various
applications such as in air-conditioning,
refrigeration , insulations ,packing materials
and as solvents.

24.  Through an international agreement known
as the Montreal Protocol on Substances that
deplete the Ozone Layer, governments have
decided to eventually discontinue production
of CFCs, carbon tetrachloride, and methyl
bromide(except for a few special uses)
Industry has developed more "ozone-friendly"
substitutes.
The ozone depletion can also cause increase in
global warming and green house effect

26. The greenhouse effect is the process in which
greenhouse gases absorbs radiation (the infra
red rays) and re- radiates it in all directions.

27. Green house effect is something that cannot be
prevented but can
be reduced. It can be reduced in the following ways:
1. By opting for greener technologies that are eco-
friendly.
2. By reducing emissions from automobiles, the
greenhouse gases can be reduced.
3. By preventing deforestation, because plants
absorb a great amount of CO2 from the
atmosphere.
4. By using CFC-free refrigerators.

28. Most of global warming is being
caused by increasing
concentrations of greenhouse gas.
Global warming refers to an
continuing rise in the average
temperature of Earth's by human
activities. Global warming can be
prevented by reducing the
emission of greenhouse gases..

29. 1. Increase in spread of disease.
2. Increase in droughts and heat waves.
3. Melting of polar ice caps.
4. Floods.
5. Storms
6. Desertification
7. Tsunamis
8. Increase in volcanic activities
9. Loss of biodiversity and animal extinction

30. Artist’s illusion of New York city
underwater.
Melting and breaking down of polar ice caps

31. This year marks the 30th anniversary of the Vienna
Convention for the Protection of the Ozone Layer, an
important milestone in the protection of the ozone
layer. The theme for the celebration of the anniversary
and this year’s International Day for the Preservation of
the Ozone Layer to be marked on 16 September is, “30
years of healing the ozone together.” The theme is
supported by the slogan, “Ozone: All there is between
you and UV.”

32. Sustainable
development
Be
informed
Understand
Know our
responsibilities
Educate
ourselves
Follow
Be
reminded

33. 1. JEENA B