2. Ozone Layer Depletion Presented by Absar Ahmed 2014-ag-4549 Ali Raza 2014-ag-4557 Zulfiqar Ali 2014-ag-4552 Sehrish Khan 2014-ag-4544 7 th Semester

3. Contents  What is Ozone Layer?  Uses of Ozone Layer  Ozone Layer Depletion  Causes Of Ozone Layer Depletion  Effects of Ozone Layer Depletion  Ozone Depletion Measures  Remedies for Ozone Layer Depletion  Conclusion  References

4. What is Ozone Layer?  The ozone layer is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet(UV) radiation.  The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million.  Every year 16 September is celebrated as Ozone Day

5. Uses Of Ozone Layer  The ozone layer absorbs ultraviolet radiation rays and prevents them from coming to the surface of the earth thus saving the human beings from harmful rays.  The ozone layer occurring naturally in the lower layers of the atmosphere helps remove the pollutants from the surface of the earth.

6. Ozone Layer Depletion  Ozone depletion describes two related phenomena observed since the late 1970s:  a steady decline of about four percent in the total amount of ozone in Earth's stratosphere (the ozone layer)  and a much larger decrease in stratospheric ozone around Earth's polar regions

7. Causes Of Ozone Layer Depletion  In recent years the thickness of this layer has been decreasing, leading in extreme cases to holes in the layer known as Ozone Hole.  The first such surprise was in 1985 when discovered that 50% of ozone was being destroyed over Antarctica  The main cause of ozone depletion and the ozone hole is man-made chemicals, especially man-made chlorofluorocarbon (CFCs), halons, referred to as ozone-depleting substances (ODS)  These compounds are transported into the stratosphere by winds after being emitted at the surface.

8. Continued….  Once in the stratosphere, they release halogen atoms through which catalyze the breakdown of ozone (O 3 ) into oxygen (O 2 ).  Ozone depletion were observed to increase as emissions of halocarbons increased.

9. Hand Over to….. Ali Raza 2014-ag-4557 BSc(Hons) Environmental Engineering 7 th Semester

10. Effects of Ozone Layer Depletion  Global warming:

11. Continued…..  Global warming, also referred to as climate change, is the observed century- scale rise in the average temperature of the Earth's climate system and its related effects.  In 2013, the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded that "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century."

12. Continue……  Green House Effect:  The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane and nitrous oxide.  The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in a planet's atmosphere warm its lower atmosphere and surface.  It was proposed by Joseph Fourier in 1824, discovered in 1860 by John Tyndall, was first investigated quantitatively by Svante Arrhenius in 1896, and its scientific description was developed in the 1930s through 1960s by Guy Stewart Callendar.

13. Effects of Global Warming  Increase in average temperatures and temperature extremes  Extreme weather events  Ice melt  Sea levels and ocean acidification  Social effects(Migration, Agriculture and Food Supply, Health, Infrastructure,,Water Resources)

14. Continued….

15. Effects of Ozone Layer Depletion  Damage to human health : If the ozone layer is depleted, it means humans will be overly exposed to strong UV light. Overexposure to strong UV light causes skin cancer, cataracts, sunburns, weakening of immune system.

16. Continued….

17. Hand Over to….. Zulfiqar Ali 2014-ag-4552 BSc(Hons) Environmental Engineering 7 th Semester

18. Continued….  Devastation to environment: Many crops species are vulnerable to strong UV light and overexposure may well lead to minimal growth, photosynthesis and flowering.

19. Continued…..  Threat to marine life: Certain marine life, especially planktons, is greatly impacted by exposure to strong ultraviolet rays. In the aquatic food chain, planktons appear high up. If planktons decrease in number due to ozone layer destruction, the marine food chain would be disrupted in many ways.

21. Continued….  Effect on animals: In domesticated animals, too much Ultraviolet radiation could also lead to skin and eye cancer.

22. Continued….  Impacts certain materials: Materials like plastics, wood, fabrics, rubber are massively degraded by too much ultraviolet radiation.

23. Ozone Depletion Measures  International Level  National Level (Singapore)  Individual Level

24. Continued….  International Level:  Montreal Protocol signed in 1987  Comprises of 189 countries now  To reduce CFC substances

25. Continued… National Level ( Singapore):  Singapore banned use of CFC products in 1991  Countries can control the import and manufacture of CFC products.

26. Hand over to….. Sehrish Khan 2014-ag-4544 BSc(Hons) Environmental Engineering 7 th Semester

27. Continued….. Individual level:  You and Me can use CFC free products  Educate and encourage others too

28. Continued……

29. Remedies for Ozone Layer Depletion

30. Continued…..  Sewage treatment before dumping waste.  Reduce combustion of fuels as the fumes result in acid rain when combined with rain  Use unleaded gasoline in vehicles.  Equip vehicles with catalytic converter.  Avoid smoking  Replace CFC,s with HCFC,s  Gain a better overall understanding on just how ozone depletion is affecting our planet.

31. Continued….  Understand Acid Deposition's causes and effects  Use alternative energy sources  Restore a damaged environment

32. Conclusive Video

33. References  http://www.brighthubengineering.com/power-plants/7369-importance- of-ozone-layer/ http://www.brighthubengineering.com/power-plants/7369-importance- of-ozone-layer/  https://www.conserve-energy-future.com/ozone-layer-and-causes-of- ozone-depletion.php https://www.conserve-energy-future.com/ozone-layer-and-causes-of- ozone-depletion.php  https://www.livescience.com/37057-global-warming-effects.html https://www.livescience.com/37057-global-warming-effects.html  http://www.ianswer4u.com/2017/01/social-effects-of-global- warming.html#axzz4yqOweI4O http://www.ianswer4u.com/2017/01/social-effects-of-global- warming.html#axzz4yqOweI4O  Google  Wikipedia