SCIENCE OF OZONE SCIENCE OF OZONE LAYER DEPLETIONLAYER DEPLETION

1212thth - 13 - 13thth March, 2007 March, 2007(JAIPUR)(JAIPUR)

By By

Rashid AyubRashid Ayub(MIS Coordinator-PMU)(MIS Coordinator-PMU)

WHAT IS OZONE ?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.

The Ozone layer forms part of the Stratosphere 10-50 The Ozone layer forms part of the Stratosphere 10-50 Km above ground levelKm above ground level

It protects the Earth form the harmful ultraviolet (UV) It protects the Earth form the harmful ultraviolet (UV) radiation especially UV-Bradiation especially UV-B

WHERE IT IS FOUND ?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.

““GOOD versus BAD” OZONEGOOD 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.

OZONE and UV-B 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.

OZONE and CFCsOZONE 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.

HOW OZONE DEPLETES ?HOW OZONE DEPLETES ?

There is a depletion of ozone in nature due to burning of There is a depletion of ozone in nature due to burning of biomass and natural emission of bromide and chlorides biomass and natural emission of bromide and chlorides from the seas, and volcanic eruptions. from the seas, and volcanic eruptions.

Around 1950s manmade chemicals, viz CFCs miracle Around 1950s manmade chemicals, viz CFCs miracle substances were used in large quantities as refrigerants substances were used in large quantities as refrigerants and aerosols. This led to severe depletion of the and aerosols. This led to severe depletion of the concentration of ozone in the stratosphere. For example,concentration of ozone in the stratosphere. For example,

CFCs CFCs UV UV Cl Cl Cl + O3---ClO + OCl + O3---ClO + O22 ClO + O3-----Cl + 2OClO + O3-----Cl + 2O22

Prof. Sherwood Rowland, M. Molina & Crutzen studied Prof. Sherwood Rowland, M. Molina & Crutzen studied this reaction and were awarded the Nobel Prize in 1995. this reaction and were awarded the Nobel Prize in 1995.

HOW OZONE LAYER IS DEPLETED ?HOW OZONE LAYER IS DEPLETED ?

CFC’s on reaching CFC’s on reaching Stratosphere gets split Stratosphere gets split by UV radiation releasing by UV radiation releasing Free ChlorineFree Chlorine

Free Chlorine enters into Free Chlorine enters into a chain reaction with a chain reaction with Ozone assisted by UV Ozone assisted by UV radiationradiation

1 Free Chlorine atom 1 Free Chlorine atom reacts with 1 lac Ozone reacts with 1 lac Ozone molecule over 100 years molecule over 100 years destroying alldestroying all

OZONE LAYER DEPLETIONOZONE 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.

IMPACT OF OZONE DEPLETIONIMPACT OF OZONE DEPLETION

Depletion of Ozone layer leads to reduced Depletion of Ozone layer leads to reduced absorption of UV radiation from the Sun.absorption of UV radiation from the Sun.

As the exposure to UV-B increases, the risk of As the exposure to UV-B increases, the risk of skin cancer, cataracts and suppressed skin cancer, cataracts and suppressed immune system increases.immune system increases.

Excessive UV-B exposure also can damage Excessive UV-B exposure also can damage terrestrial plant life, micro-organisms and terrestrial plant life, micro-organisms and aquatic eco-systems. aquatic eco-systems.

INTERNATIONAL ACTIONINTERNATIONAL ACTION

Dr Molina and Dr Sherwood had forecast in 1974 that Dr Molina and Dr Sherwood had forecast in 1974 that with consumption of 1 million tonnes of CFC’s with consumption of 1 million tonnes of CFC’s annually 50 % of Ozone Layer would be destroyed by annually 50 % of Ozone Layer would be destroyed by 20502050

The above prediction gave impetus to international The above prediction gave impetus to international action to meet the environmental challenge action to meet the environmental challenge

United Nation Environment Programme (UNEP) had United Nation Environment Programme (UNEP) had played the leading role. played the leading role.

In March 1985 the VIENNA Convention for the In March 1985 the VIENNA Convention for the Protection of the Ozone Layer was created. The Protection of the Ozone Layer was created. The obligations of the Parties were: cooperation in obligations of the Parties were: cooperation in research; exchange of information; adopt policies to research; exchange of information; adopt policies to control human activities to protect ozone layer.control human activities to protect ozone layer.

INTERNATION ACTIONINTERNATION ACTION In May 1985, British Scientists led by Dr. Farman reported on In May 1985, British Scientists led by Dr. Farman reported on

empirical basis 30-40% depletion in the Antarctic Ozone hole empirical basis 30-40% depletion in the Antarctic Ozone hole since 1977since 1977

Scientific community requested urgent remedial actions.Scientific community requested urgent remedial actions.

This global concern culminated in the signing of the Montreal This global concern culminated in the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer on 16 Protocol on Substances that Deplete the Ozone Layer on 16 September 1987 delineating the specific plan of action for September 1987 delineating the specific plan of action for phasing out ODS for saving the Ozone layer.phasing out ODS for saving the Ozone layer.

It has so far enlisted 95 substances as ODS for phasing out as 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 per a given schedule. The important one’s are :CFC’s ; Halons ; HCFC’s ; CTC’s ; Methyl Chloroform and Methyl Bromide ; HCFC’s ; CTC’s ; Methyl Chloroform and Methyl Bromide

INDIA’s SCENARIOINDIA’s SCENARIO India either produces or consumes 9 controlled India either produces or consumes 9 controlled

substancessubstances

CFC-11, CFC-12, CFC-113(a)CFC-11, CFC-12, CFC-113(a)

Halon-1211, Halon-1301Halon-1211, Halon-1301

CTCCTC

HCFC-22HCFC-22

Methyl Bromide, Methyl ChloroformMethyl Bromide, Methyl Chloroform

LIST OF CONTROLLED SUBSTANCESLIST 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.

Substances Production ConsumptionCFC-11 Yes YesCFC-12 Yes YesCFC-113 Yes YesHalon-1211 No Yes**Halon-1301 No Yes**Methyl Chloroform No YesCarbontetrachloride Yes YesMethyl bromide No Yes*HCFC-22 Yes Yes

* Quarantine & Pre-shipment / ** Servicing of existing equipment.

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

ODS / Baseline (Prod. & Cons.)

2005 2007 2010 2015 2040

CFC – P(22588 MT)

C(6681 MT)

50 % 85 % 100 % NA NA

Halon – P( 95 MT)

C(260 MT)

50 % - 100 % NA NA

CTC – P(10507 MT)

C(10459 MT)

85 % - 100 % NA NA

MCF – P( Nil )

C(1467 MT )

30 % - 70 % 100 % NA

MeBr – P(108 MT)

C( - )*

20 % - - 100 % NA

HCFCs** - - - - 100 %

ODS USED IN SECTORSODS USED IN SECTORS Sector Sector ODS UsedODS Used SubstitutesSubstitutes

1. 1. Foam Foam CFC-11CFC-11 HCFC-141bHCFC-141b

2. 2. RACRAC CFC-11, CFC-12CFC-11, CFC-12 HCFC-22, HCFC-123 HCFC-22, HCFC-123

3. 3. AerosolAerosol CFC-11, CFC-12CFC-11, CFC-12 Hydrocarbon AerosolHydrocarbon AerosolPropellants (HAPs)Propellants (HAPs)

4. 4. Solvent Solvent CTC, MCHCTC, MCH Trichloroethylene etc.Trichloroethylene etc.CFC-113CFC-113

5. 5. Fire Ext.Fire Ext. Halon–1211/1301 Halon–1211/1301 ABC Powder, CO2ABC Powder, CO2

6. 6. Q & P Q & P Methyl Bromide Methyl Bromide --

CONTACT USCONTACT US

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www.ozonecell.comwww.ozonecell.com

Our Email:-Our Email:-

Ozone-mef@nic.inOzone-mef@nic.in