This presentation is about the depletion of ozone layer & the solution of it

1. Ozone Layer Depletion
PREPARED BY:
NASIB BIN MAHBUB

2. Ozone layer
 Situated in troposphere & stratosphere
 From about 20-30 km above the earth’s surface
 Contains about 90% of the atmospheric ozone
 Two types of ozone –
 Stratospheric ozone (Good Ozone)
 Tropospheric ozone (Bad Ozone)

3. Formation of ozone layer
 Chapman cycle
 Photochemical reaction : Conversion of atmospheric oxygen into ozone(O3) in
presence of sunlight, hot temperature & chemical catalysts
 Catalysts : Hydroxy
Nitric Oxide
Atomic Chlorine
Bromine

4. Chapman cycle
 ozone is continuously produced and destroyed
 through PHOTOCHEMICAL REACTIONS in the stratosphere
 involves oxygen (O2), molecular oxygen (O), photons of UV radiation, and
OZONE (O3).
Ozone being formed
naturally
Ozone being
destroyed
naturally
Ozone being
destroyed
naturally
Ozone being formed
naturally

5. Ozone Layer Depletion
 Thinning of ozone layer
 Most pronounced decrease in ozone has been in the lower stratosphere
 Not measured in terms of ozone concentration but by reduction in the
total column of ozone

6. Ozone Depleting Chemicals
 Chlorofluorocarbons / Freon (CFCs)
 Halons (haloalkane / Halogenoalkane)
 Methyl Bromide (CH3Br)
 Methyl Chloroform (CH3CCl3)
 Hydrogen Chloride (HCl)
 Nitrous Oxide (N2O)
Methyl
Bromide, 6%
Aerosls, 22%
Foams, 8%
Halons, 11%
Refrigeration
Manufacturing,
19%
Refrigeration
Servicing, 3%
OZONE DEPLETING SUBSTANCES

7. Chlorofluorocarbon
Sources: Refrigerants, Aerosols, Propellants, Fire extinguisher with halons
CFC 11
26%
CFC 12
32%
CFC 113
7%
HCFC
3%
CCl3CH3
11%
HCL &
CH3Cl…
PERCENTAGE OF OZONE
DEPLETING CHLORINE
SOURCES

8. Importance of Ozone layer
 Filters harmful ultraviolet radiation
 Protect the earth from harmful radiation
 Polar ice shifting
 Helpful to reduce temperature

9. Effects of ozone depletion
 Human health
 Worse sunburn
 More eye cataracts
 Skin cancers
 Immune system suppression
 Food and forests
 Reduced yields for some crops
 Reduced seafood supplies from reduced phytoplankton
 Decreased forest productivity for UV – sensitive tree species

10. Effects of ozone depletion
 Air pollution and materials
 Increased acid deposition
 Increased photochemical smog
 Degradation of outdoor paints and plastics
 Global warming
 Accelerated warming because of decreased ocean uptake of CO2 from
atmosphere by phytoplankton and CFCs acting as greenhouse gases.

11. Prevention of ozone layer depletion
 Limit private vehicle driving
 Using eco-friendly household cleaning products
 Reducing usage of aerosol, insecticides and pesticides
 Developing stringent regulation for rocket launches
 Banning the use of dangerous nitrous oxide
 Avoid smoking
 Producing more fuel efficient vehicles
 Afforestation
 Reducing usage of air conditioners
 Reduce foam packaging
 Enforcement of Montreal Protocol

12. Montreal Protocol
• A phase-out management plan to reduce ozone depleting substances
• Signed in 1987 under UNEP to Protect ozone layer
• Approved by 197 members of UN
• 16 September – Ozone day

13. Success of Montreal Protocol

14. Thank You