1. PRESENTERS:
Maria Malik
Umm e hani
Hussnain Ali

2. OZONE DEPLETION
(OZONE HOLE)

3. OZONE LAYER
The ozone layer is a layer in the earth’s atmosphere which contains 90% of atmospheric ozone (O3). The ozone layer is found in the lower portion of the stratosphere from about 20 to 30 km above earth’s surface. It’s thickness varies seasonly and geographically.
20-30 20

4. FORMATION OF OZONE LAYER
The ozone layer or the ozone forms by conversion of atmospheric oxygen(O2) into ozone (O3), this process is called as Chapman cycle . The oxygen get photolyzed by UV. rays to form oxygen radical. O2
U.V. Light 2 O

5. The oxygen radical then react with molecular oxygen and forms ozone molecule (O3).
At the same time ozone gets reduce to oxygen by reacting with oxygen radical. O3 O2 2 O
So, ozone is constantly get created and destroyed by Chapman cycle, which is a natural process.

6. OZONE DEPLETION
Decrease in concentration of ozone and thinning of ozone layer is called Ozone depletion.
From industries and our day to day life many gases like Chlorofluorocarbons (CFC’s) , Hydro- chlorofluorocarbons (HCFC’s) , halons, halogens, etc. get evolved in atmosphere which are mainly responsible for ozone depletion, as it contains or produce Chlorine (Cl) atom.

7. OZONE HOLE
As a result of ozone depletion, over Antarctica the ozone hole is formed. This ozone hole leads to melting of ice of Antarctica, increase in sea level and other harmful effects on it’s environment.

8. OZONE DEPLETING SUBSTANCES
Ozone depleting substances are mainly CFC’s, HCFC’s, Halons, etc. which are found in Refrigerators, Cleaning agents, sprays, Pesticides, Air conditioners, car emissions, etc.

9. EFFECT OF OZONE DEPLETION
Due to ozone depletion harmful U. V. Rays such as UV-B Radiation reaches to earth which leads to harmful effects on animals, plants, aquatic life as well as on humans.
Effect on Materials: Degradation of paints and plastics.
Effect on Climate: Global Warming (Increasing the Average temperature of the Earth’s surface).

10. Effect on Human Health:
Damage genetic materials in the cells.
Leads to more people suffering from Cataracts.
Causes cancer, allergies and some other infectious disease.
10% depletion in ozone layer results in 30% increase in skin cancer infection.

11. PREVENTIONS
Limit private vehicle driving to decrease vehicle emissions.
By using Eco-friendly household or other cleaning agents.
Avoid excess use of pesticides. Replacing CFC’s by other material which are less damaging.
Manufacturing and using of ozone depleting chemicals must be stopped, etc.

12. But, for controlling ozone depletion the most important thing is to aware people about it,
and that’s why International Environmental Community declared 16 September as a World Ozone Day .