Ozone is a harmful gas composed of three oxygen atoms, primarily found in the stratosphere where it forms a protective ozone layer that absorbs harmful UV radiation. Human activities, particularly the use of CFCs and other ozone-depleting substances, have led to significant thinning of this layer, notably the 'ozone hole' discovered in the 1980s. The Montreal Protocol is an international treaty aimed at phasing out the production of substances that deplete the ozone layer.

1. BY,
SONIYA THANKACHAN
M2 Chemistry

2.  O3
 a gas composed of three atoms of
oxygen
 bluish gas that is harmful to breathe
 Nearly 90% of the Earth's ozone is in
the stratosphere and is referred to as
the ozone layer
 Ozone absorbs a band of ultraviolet
radiation called UVB

3. HOW OZONE IS FORMED?

4. IMPORTANCE OF
OZONE LAYER
 The ozone molecule form a gaseous layer
in the earth’s upper atmosphere called
stratosphere.
 Ozone present in the stratosphere forms a
protective layer is known as ozone layer
 It was discovered in 1913 by the French
physists Charles fabry and Hentry Buisson
 It shields earth from harmful radiation uv
radiation that comes from sun.

5.  During the last several decades human activities
have resulted in considerable reduction in the
ozone layer of the atmosphere.
 When Uv light wave strike CFC molecule in the
upper atmosphere,a carbon chlorine bond breaks
producing a chlorine atom .The chlorine atom then
react with an ozone molecule ,breaking it apart and
so destroying the ozone.

7.  In the 1980’s scientists discovered that the ozone
layer was thinning in the lower stratosphere with
particularly dramatic ozone loss known as the
“ozone hole” in the Antarctic spring time. This is
caused by increasing concentration of ozone –
depleting chemicals in the stratosphere that comes
from mainly

9.  CFC from
 1.Aerosols(spray propellants)
2.Refrigeration and air Conditioning
3.Plastic foams
 4.Industrial solvents
5.Sterilants for medical
supplies

10.  HCFCs,
 Halons
 methyl bromide
 carbon tetrachloride
 methyl chloroform.

13.  Buy air-conditioning and refrigeration
equipment that do not use HCFCs as
refrigerant.
 Buy aerosol products that do not use HCFCs
or CFCs as propellants.
 When motor vehicle air conditioners need
servicing, make sure that the refrigerants are
properly recovered and recycled instead of
being vented to the atmosphere.

14. The montreal protocol on substances that
deplete the ozone layer is an international
treaty designed to protect the ozone layer by
facing out the production of numerous
substances that are responsible for ozone
depletion.