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SCIENCE OF OZONE LAYER DEPLETION 12 th - 13 th March, 2007 (JAIPUR)

SCIENCE OF OZONE LAYER DEPLETION 12 th - 13 th March, 2007 (JAIPUR). By Rashid Ayub (MIS Coordinator-PMU). WHAT IS OZONE ?. Ozone is a tri-atomic form of oxygen. Ozone is a gas that is naturally present in our atmosphere. Acts as an umbrella.

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SCIENCE OF OZONE LAYER DEPLETION 12 th - 13 th March, 2007 (JAIPUR)

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  1. SCIENCE OF OZONE LAYER DEPLETION12th - 13th March, 2007(JAIPUR) By Rashid Ayub (MIS Coordinator-PMU)

  2. WHAT IS OZONE ? • Ozone is a tri-atomic form of oxygen. • Ozone is a gas that is naturally present in our atmosphere. Acts as an umbrella. • Ozone is formed throughout the atmosphere in multi-step chemical processes that require sunlight. • The process begins with the breaking apart of an oxygen molecule by UV from the sun.

  3. The Ozone layer forms part of the Stratosphere 10-50 Km above ground level • It protects the Earth form the harmful ultraviolet (UV) radiation especially UV-B

  4. WHERE IT IS FOUND ? • About 10% of atmospheric ozone is found in the Troposphere. (the region closet to the earth surface from 10-16 kms / 6-10 miles • The remaining 90% of Ozone resides in the Stratosphere (in a region that begins about 10-50 km above Earth’s surface commonly known as Ozone Layer which is part of the stratosphere. • If all the ozone molecules in the stratosphere are compressed it will result in a thickness of 300mm.

  5. “GOOD versus BAD” OZONE • Ozone in the stratosphere, absorbs the sun’s biologically harmful UV radiation, because of this beneficial role, stratospheric ozone is considered as “Good Ozone” • In contrast, ozone at earth’s surface that is formed from pollutants is considered as “Bad Ozone” because it can be harmful to humans, plants and animal life.

  6. OZONE and UV-B • The ultraviolet radiation (UV) which is invisible is constantly emitted from the Sun. • UV-B and UV-C are highly energetic and dangerous to life on earth. • UV-A being less energetic is not dangerous. • UV-C is absorbed strongly by oxygen in atmosphere • UV-B is absorbed by Ozone Layer in the stratosphere and only 2-3% of it reaches the earth’s surface.

  7. OZONE and CFCs • CFCs were first synthesized in 1928 for its application use in refrigerants, solvents, foam, aerosols etc. • CFCs were/are very stable and do not dissolve in rain. • There is no natural processes that can remove the CFCs from the lower atmosphere. • Over the time, the CFCs only diffuses into the stratosphere and strong UV radiation can breaks them down. And when that happens, CFC releases highly active atomic Chlorine • Finding suggests that one chlorine atom can destroy over 1,00,000 ozone molecules.

  8. HOW OZONE DEPLETES ? There is a depletion of ozone in nature due to burning of biomass and natural emission of bromide and chlorides from the seas, and volcanic eruptions. Around 1950s manmade chemicals, viz CFCs miracle substances were used in large quantities as refrigerants and aerosols. This led to severe depletion of the concentration of ozone in the stratosphere. For example, • CFCs UV Cl • Cl + O3---ClO + O2 • ClO + O3-----Cl + 2O2 Prof. Sherwood Rowland, M. Molina & Crutzen studied this reaction and were awarded the Nobel Prize in 1995.

  9. HOW OZONE LAYER IS DEPLETED ? • CFC’s on reaching Stratosphere gets split by UV radiation releasing Free Chlorine • Free Chlorine enters into a chain reaction with Ozone assisted by UV radiation • 1 Free Chlorine atom reacts with 1 lac Ozone molecule over 100 years destroying all

  10. OZONE LAYER DEPLETION • Ozone Depleting Substances :- CFC, Halon, CTC, Methyl Chloroform, Methyl Bromide and HCFC. • These chemicals are broken down by the UV radiation and release extremely reactive chlorine or bromine atoms. • Chlorine / Bromine atoms undergoes a series of catalytic reactions leading to destruction of ozone.

  11. IMPACT OF OZONE DEPLETION • Depletion of Ozone layer leads to reduced absorption of UV radiation from the Sun. • As the exposure to UV-B increases, the risk of skin cancer, cataracts and suppressed immune system increases. • Excessive UV-B exposure also can damage terrestrial plant life, micro-organisms and aquatic eco-systems.

  12. INTERNATIONAL ACTION • Dr Molina and Dr Sherwood had forecast in 1974 that with consumption of 1 million tonnes of CFC’s annually 50 % of Ozone Layer would be destroyed by 2050 • The above prediction gave impetus to international action to meet the environmental challenge • United Nation Environment Programme (UNEP) had played the leading role. • In March 1985 the VIENNA Convention for the Protection of the Ozone Layer was created. The obligations of the Parties were: cooperation in research; exchange of information; adopt policies to control human activities to protect ozone layer.

  13. INTERNATION ACTION • In May 1985, British Scientists led by Dr. Farman reported on empirical basis 30-40% depletion in the Antarctic Ozone hole since 1977 • Scientific community requested urgent remedial actions. • This global concern culminated in the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer on 16 September 1987 delineating the specific plan of action for phasing out ODS for saving the Ozone layer. • It has so far enlisted 95 substances as ODS for phasing out as per a given schedule. The important one’s are :CFC’s ; Halons ; HCFC’s ; CTC’s ; Methyl Chloroform and Methyl Bromide

  14. INDIA’s SCENARIO • India either produces or consumes 9 controlled substances • CFC-11, CFC-12, CFC-113(a) • Halon-1211, Halon-1301 • CTC • HCFC-22 • Methyl Bromide, Methyl Chloroform

  15. LIST OF CONTROLLED SUBSTANCES As per Article 2 of the Montreal Protocol, the total number of controlled substances are 95. The following 9 controlled substances are produced and consumed in India. SubstancesProductionConsumption CFC-11 Yes Yes CFC-12 Yes Yes CFC-113 Yes Yes Halon-1211 No Yes** Halon-1301 No Yes** Methyl Chloroform No Yes Carbontetrachloride Yes Yes Methyl bromide No Yes* HCFC-22 Yes Yes * Quarantine & Pre-shipment / ** Servicing of existing equipment.

  16. PRODUCTION & CONSUMPTION CONTROL SCHEDULE AS PER MONTREAL PROTOCOL AND INDIA’S POSITION

  17. ODS USED IN SECTORS Sector ODS UsedSubstitutes 1. Foam CFC-11 HCFC-141b 2. RAC CFC-11, CFC-12 HCFC-22, HCFC-123 3. Aerosol CFC-11, CFC-12 Hydrocarbon Aerosol Propellants (HAPs) 4. Solvent CTC, MCH Trichloroethylene etc. CFC-113 5. Fire Ext. Halon–1211/1301 ABC Powder, CO2 6. Q & P Methyl Bromide -

  18. CONTACT US Our Website:- www.ozonecell.com Our Email:- Ozone-mef@nic.in

  19. THANK YOU

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