What is OZONE Layer Depletion :
PROPOSITIONAL :
There are different amounts of gases in the atmosphere. In which the ozone layer is located in the stratosphere, which is moving towards the top of the earth.
Its thickness is approximately 300 Dobson units (1 Dobson unit = 0.01 mm). And 90% of the ozone is mainly located in the area of 10 to 17 km. whose atomic formula is O³.
 |
| OZONE LAYER DEPLETION |
Formation of Ozone Gas :
Oxygen in the atmosphere. Ozone is formed due to the collision of the solar radiations of the air with the ultraviolet radiations (ultraviolet – UV).
Oxygen + photon (solar light) → 2 oxygen + oxygen , Ozone is not a stable gas it is again converted into oxygen atom by reacting with oxygen. molecular oxygen molecule. 0 + 0 - 20, thus, the natural cycle of ozone and oxygen is running.
Sidney Chapmele in AD. In 1930, the concept of ozone-oxygen cycle was given. So the ozone layer is also called Chapman cycle.
Ozone Chronology :
1840: Discovery of ozone in the laboratory by Christian Schoenbein.
1913 : French Physicists Charles Fabry & Henry Buissm discover the absence of ozone in the Earth's lowest layer.
1920 : CFCs are discovered as an alternative to ammonia.
1985 : Discovery of polar ozone gap by British scientists (first ozone gap occurred in Antarctica).
1987 : Montreal Protocol
1996: Ban on CFCs and other Ozone Depleting Substances.
2030 : Phase out HCFCs completely.
Things to Know :
CFCs are the most potent component of ozone depletion.
Ozone depletion in Antarctica decreases from winter to spring. The maximum effect occurs in September-November.
There are two types of causes of ozone depletion :
(1) Natural causes (2) Man-made causes.
Natural causes :
Solar radiation: When sunspots increase on the surface of the sun, the energy from the sun increases. Therefore, when the energetic particles (Changed Particles) coming from the sun enter the atmosphere, they collide with the nitrogen and water molecules in the atmosphere.
As a result of this collision, nitrogen and oxygen atoms are released, which process with ozone and dissolve in its layer.
Man-made causes :
Decomposition of ozone by man-made processes such as chlorine, bromine, fluorine react with ozone when concentrated in the isothermal mantle.
The gases that play a major role in ozone depleting gases (chlorine, fluorine, bromine) are called halogen gases, also known as halocarbons.
Important ozone depleting gases :
(1) Chlorofluorocarbons (CFCs) or Freons
(2) Halon (BrF, ), Bromotrifluoromethane (BTM 1301)
(3) Hydrobromofluorocarbons (HBFC)
(4) Carbon tetrachloride (CI)
(5) Methyl Chloroform (CH.CCI.)
(6) Methyl Bromide (CH.Br)
(7) Bromochloromethane (CH,BrCl)
(8) Hydrochlorofluorocarbons (HCFCs) also known as ferrons.
(9) Nitrogen oxides (NOx) of which gases number 1 to 7 are banned under the Montreal Agreement.
The first ozone hole occurred in Antarctica.
Fluorofluorocarbon (CFC) or Freon :
The most powerful component responsible for ozone depletion: As a coolant in refrigerators and air conditioners As a forming agent in plastic manufacturing in aerosol sprays.
There are 2 forms of CFC gas : (1) CFC-11 (2) CFC-12.
51% contribution to ozone depletion.
Hydro Chlorofluoro Carbon :
Hydro Chlorofluoro Carbon is responsible for ozone depletion and also contributes to global warming.
Halon and Hydro Bromo Fluorocarbon.
Both for bromine-containing compounds: us: as fire extinguishers.
Bromine compounds are very harmful to the ozone layer because the ozone depleting potential of the bromine molecule is 100 times greater than that of chlorine.
Effects of Ozone Layer Depletion :
If the mantle is eroded, more UV rays will reach the Earth's surface. UV-B waves will reach the Earth in the greatest amount. Due to this, there will be strange effects on the Earth's biosphere.
Effects On Vegetation :
Vegetation growth is indirectly affected due to increased amount of UV-B radiation.
Vienna Convention (1985) :
Convention for the Protection of the Ozone Layer was held at the global level in 1985. It came into force in 1988.)
The Vienna Convention is a multilateral environmental agreement and is also known as the Framework Convention.
In 2009 the Vienna Convention became the first convention in the world to achieve sovereign ratification, i.e. approval by the governments of each signatory country. The Vienna Convention does not make any binding rules to reduce the use of CFCs.
Montreal Protocol :
The Montreal Protocol is an international agreement designed to reduce the production and consumption of ozone-depleting substances in order to reduce the concentration of ozone depleting substance in the atmosphere and the fragile earth's atmosphere.
The ozone layer in the state should be protected.
The Montreal Accord was opened for signature on September 16, 1987.
197 countries of the world have signed it. The Montreal Accord entered into force on January 1, 1989.
Since the Montreal Agreement was presented for signature on 16 September, 16 September is celebrated annually by the United Nations General Assembly as 'International Ozone Testing Day'. It is also celebrated as Ozone Day.
Theme of Ozone Day on September 16, 2017: 'Caring for all life under the sun' .
Under the Montreal Protocol, efforts have been started to reduce the production and use of gases like CFC, Halon, Carbon Tetrachloride, Methyl Chloroform, HBFC, CH, Br, CH, BrCI.
Various conferences have been organized to assess progress on the Montreal Accord. The 27th Convention of the Montreal Protocol was held in Dubai in November 2015.
In the Dubai Pathway (27th Convention), most of the emphasis was placed on banning HFCs.
The Montreal Protocol aims to completely ban HCFCs by 2030, while for HFCs it has been decided to phase out HFCs by 2045 under the amendments made in Kigali, Rwanda in October 2016.
Eliminating HFCs is likely to reduce the Earth's temperature by 0.5 C by the end of the century.
India and Montreal Agreement:
India AD Since 1991 the Vienna Convention as well as Since 1992, the country is a partner of the Montreal Agreement.
Since 1993, India has worked with UNEP to eliminate ozone-depleting gases. India uses some ozone depleting substances (ODs) in the production and export of 'metered dose inhalers' in the health sector.
The production and use of CFC, carbon tetrachloride and halon has been gradually banned from January 1, 2010.
India is trying to phase out production and use of HCFCs by 2030. Carbon tetrachloride is being used in the steel industry, it has now been replaced by tetrachloroethane.
Ozone Cell has been formed under the Ministry of Environment, Forest and Climate Change, so that India can fulfill its responsibilities properly.
