This presentation gives a brief description of what atmosphere is and its importance, the structure making up the atmosphere and the ozone layer.

1. The Atmosphere
Composition and structure of the atmosphere
By N.Nkosi

2. Composition of the
atmosphere
 Atmosphere are thin layers of gases
surrounding the Earth.
The atmosphere is made up of different
gases, that are essential for life on
earth.
These gases in the atmosphere
includes:
 Nitrogen 78%
 Oxygen 21%
 Argon 0.9%
 Carbon dioxide 0,04%
 Other gases 0.1%
(Mas, 2013).

3. The importance of the atmosphere
 The atmosphere protects life on earth by blocking the
harmful incoming ultraviolet (UV) radiations from the sun.
 It consist of oxygen which is essential for respiration in
humans.
 It allows weather and climate to occur.
 It prevents extreme temperatures on earth between day
and night.
 Carbon dioxide is used for photosynthesis.
 Nitrogen needed for plant growth.
(Kotze, 2015)

4. Structure of the atmosphere
 The atmosphere is structured in 4 distinct layers.
1. Troposphere
2. Stratosphere
3. Mesosphere
4. Thermosphere
(Nighat, 2015).

5. Layers of the
atmosphere
(IshikaDahiya2, 2022)

6. Layers of the atmosphere conti…
Troposphere
 The closest layer to the earth.
 It extends to about 25 km above the earth`s surface.
 All weather processes occur here, passenger planes can
fly in the tropopause.
 Temperature decreases with increase in altitude.
 Upper limit of the troposphere is the tropopause.
(Kotze, 2015).

7. Layers of the atmosphere conti..
Stratosphere
 Second layer of the atmosphere above the troposphere.
 Contains ozone layer.
 It extends to about 25-50 km above the earth`s surface.
 Free from weather disturbance and is suitable for flying
aircraft.
 Upper limit of the stratosphere is the stratopause.
(Nighat, 2015).

8. Layers of the atmosphere conti…
Mesosphere
 This is the third layer of the atmosphere above the
stratosphere.
 It extends to about 50-85 km above the earth`s surface.
 Temperatures decreases with altitude, making this layer
the coldest layer.
 It receives meteoric dust that end up forming nuclei.
 Upper limit of the mesosphere is the mesopause.
(Kotze, 2015)

9. Layers of the atmosphere conti…
Thermosphere
 Uppermost layer of the atmosphere.
 It extends from 85-600 km above the earth`s surface.
 Temperature increases with increase in altitude, making
this the hottest layer.
 Contains ionosphere.
 Uppermost layer of the thermosphere is called the
thermopause.
(IshikaDahiya2, 2022).

10. Ozone layer of the atmosphere
Ozone- is an O₃ molecule containing of 3 oxygen atoms.
This layer is found in the stratosphere. The ozone layer
absorbs harmful ultraviolet (UV) rays from the sun protecting
the earth.
Ozone depletion- is the decrease of the ozone concentration
in the ozone layer.
(Satiishrao, 2016).

11. Causes of ozone
depletion
 Chlorofluorocarbons (CFC`S) the
aerosols, air conditioners and
refrigerators.
 Methane from burning fossil
fuels, animals and wetlands.
 Methyl bromide in pesticides.
(Satiishrao, 2016).
TheOzone depletion process

12. Effects of ozone depletion
 Increases risks of skin cancer.
 Can cause eye disease, cataracts.
 Weakens the immune system.
 Disrupts marine food chains.
 Increases smog formation.
(Satiishrao, 2016).

13. Ways to reduce the ozone layers
 Avoid the use of dangerous gases (CFC`s).
 Apply fines on companies that use gases that may cause
harm on the ozone layer.
 Reduce using cars, try using bicycles walking or do
carpool.
 Do not use cleaning products and sprays that are harmful
to the environment.
 Maintain air conditioners.
(Satiishrao, 2016).

14. Reference list
Kotze, L. (2015) 3 atmosphere. Available from Slideshare at
https://www.slideshare.net/LKOTZE/3-atmosphere (Accessed 21 August 2022).
Mas, P., B. (2013). Earth`s atmosphere. Available from Slideshare at
https://www.slideshare.net/psychopamtic/earths-atmosphere-27966245 (Accessed 21 August
2022).
Nighat, N. (2015). Atmosphere. Available from Slideshare at
https://www.slideshare.net/NaginaNighat/atmosphere-53933416 (Accessed 21 August 2022).
IshikaDahiya2. (2022). Composition and structure of the earth`s atmosphere. Available from
Slideshare at https://www.slideshare.net/IshikaDahiya2/composition-and-structure-of-earths-
atmosphere (Accessed 21 August 2022).
Satiishrao. (2016). Ozone depletion. Available from Slideshare at
https://www.slideshare.net/satiishrao/ozone-depletion-58711140 (Accessed 21 August 2022).