Stratospheric pollution refers to depletion of the ozone layer by compounds like CFCs. The ozone layer protects us from harmful UV radiation from the sun, which can cause skin cancer. Ozone is formed when UV radiation splits oxygen molecules, and the oxygen atoms combine with other oxygen molecules. CFCs released into the atmosphere rise up and are broken down by UV radiation, releasing chlorine which destroys ozone. This has caused an ozone hole to form over Antarctica in recent decades. Increased UV radiation damages skin, eyes, marine life, plants and more.

1. CHEMISTRYPPT
Stratosphericpollution

2. Stratospheric Pollution means
depletion of the ozone layer
(ozone hole) by certain
compounds like oxides of
nitrogen, chlorofluorocarbons
(CFCs).
What is meant by
stratospheric pollution?

3. WHYDOWE NEEDOZONELAYER ?
 The upper stratosphere consist of
considerable amount of ozone which
protect us from the harmful ultravoilet
radiation coming from the sun.
 These radiation causes skin cancer in
the humans.

4. FORMATIONOF OZONELAYER
+ Ozone is a product of UV radiations acting
on oxygen molecules.
 The UV radiation split molecular
oxygen into free oxygen atom. These
oxygen atoms combine with molecular
oxygen to form ozone.
 Ozone is thermodynamically unstable
and decomposes to molecular oxygen.
 O2 (g) O (g) +O (g)
 O (g) +O2 (g) O3
UV

5. OZONELAYERDEPLETION
 The main reason for ozone layer depletion is
believed to be the release of
chlorofluorocarbon(CFC),also known as
freons.
 These compound are non-reactive,non-
flammable,non-toxic organic molecules and
therefore used in
refrigerator,airconditioner, In the production
of plastic foams and by the electronic
industry for cleaning electronic parts.

6. DEPLETONOF OZONELAYER
Once CFCs are released in
atmosphere they mix with normal
atmospheric gases and eventually
reach stratosphere and get broken
down by powerful UV radiation.

7. OZONEHOLEINANTARTICA
 In 1980s atmospheric scientists
working in Antartica reported ozone
hole.
 In summer season, nitrogen dioxide
and methane react with chlorine
monoxide and chlorine atoms forming
chlorine sinks preventing much ozone
depletion.

8. 0ZONELAYERINANTARTICA
 Clo(g)+No2(g) CloNo2(g)
 Cl(g)+CH4(g) CH3(g)+Hcl(g)
In winter it forms:
 CloNo2(g)+H2O(g)
Hocl(g)+HNO3(g)
 CloNo2(g)+Hcl(g) Cl2(g)+HNO3(g)
In spring it again:
 Hocl(g) OH(g)+Cl(g)
 Cl2(g) 2Cl(g)

9. EFFECTSOF OZONELAYERDEPLETION
 UV radiation lead to ageing of
skin,cataract,sunburn, skin cancer,killing of
many phytoplanktons,damage to fish
productivity.
 Plant proteins get easily affected by UV
radiation which lead to harmful mutation of
cells.
 It also increase evaporation of surface water
through the stomata of the leaves and
decrease moisture content In soil.
 Increase in UV radiation damage paints and

10. BY
ROSHANAKTHAR
&
ABDULRASHEEDA