Ozone Layer Depletion explained | Protocols for prevention of Ozone Depletion

Let us Discuss the formation of ozone layer first which will help to understand its depletion better.

Ozone Layer Depletion

Formation of Ozone (O3):

When molecular oxygen(O2) comes in contact with sunlight (UV) it breaks oxygen into two monoatomic oxygen radicals. Formation of nascent oxygen (single atom of oxygen) also known as monoatomic oxygen radical which is quiet simple. This nascent oxygen is highly unstable and very reactive with anything.

Chemical reaction involve is

Sunlight (UV)

          O2  一一一一一一一> [O]  +  [O]

This nascent oxygen is combined with another surrounding oxygen molecule which results in the formation of  ozone which is triatomic oxygen molecule.

O2  +  [O]   一一一一一一一一>   O3

Ozone layer depletion:

Ozone is present in the stratosphere which is naturally occurring substance present in the form of thin layer. This stratospheric ozone is also known as good ozone since it protects us from harmful UV radiation. 

Ozone layer depletion is the phenomenon in which the thickness of ozone layer is getting reduced than before, depletion does not mean that the hole is being developed.

These ozone molecules further dissociates into other atoms and this dissociation undergoes chain reaction till the catalyst consumes in the reaction. This catalyst is obtained from compounds such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) and such compounds released from refrigerators and other industrial chemicals. Chemical reaction is

As these compound migrate towards higher altitude in the stratosphere region and when these compounds comes in the contact of sunlight these compounds breaks into atomic chlorine and bromine. When these atomic chlorine and bromine comes in the contact of ozone results in formation of hypochlorite (ClO) and oxygen (O2). The chain reaction is as given bellow

Just for the purpose of understanding one Cl atom destroys nearly the 1,00,000 ozone atoms.  And thats Huugee

Impact of ozone layer depletion:

One major impacts we all can understand that the stratospheric ozone is behaving as a shield for the entire living organisms. If ozone layer gets thin at various places than it is easier for the short wave ultraviolet rays to gets enter into earth atmosphere. Even if the small amount of UV radiation comes in contact with humans it may become the cause of change in DNA structure, Certain type of skin cancers, eyes cataract. In plants UV radiation destroys the chlorophyll.

Major ozone depleting substance(ODS):

• chlorofluorocarbons(CFCs)
• hydrochlorofluorocarbons(HCFCs)
• Methyl Bromide
• Carbon tetrachloride
• Methyl chloroform
• Freons

Prevention of ozone depletion layer:

It is not a new thing that we are contaminating our environment by using various types of pollutants, industrial chemical waste, plastics, solid waste, harmful radiations. But if this contamination crosses certain level of limits which nature allows us than it results in some serious problem for both humans as well as for nature. Various restrictions were imposed for both developed  and developing nations through montreal protocol and its amendment.

Some of the most important protocols up to 2020 for Ozone layer are:

The Montreal protocol:

Under this protocol, developed and developing countries must have to fulfill the legal procedure within the stipulated time period. This protocol adopted on 15 September 1987  and also has been ratified by all the countries - 197 UN member. Montreal protocol phases out consumption and production of nearly 100 man made chemical substance.

The protocol includes provision related to control measures, Calculation of control levels, Control of trade with non- parties, Special situation of developing countries, Reporting of data, Non compliance, Technical assistance specially for developing countries. The ODS which were phased out by this protocol CFCs, Carbon tetrachloride, Methyl chloroform, HCFCs, Methyl bromide, HFCs.

The Montreal amendment:

When The Montreal protocol was implemented it was considered that HCFCs are the gases used in the refrigeration and air conditioning and foam application is the major ODS but not the major greenhouse gas.

Keeping the fact in mind that the global warming potential (GWP) of HCFCs is 2000 times greater than the GWP of carbon dioxide. In september 2007 all the member nation took strong decision towards the reduction or being phased out of HCFCs. The developed countries must have to completely phased out the use of HCFCs by 2020, And developing countries must have to phased out the use of HCFCs by 2030.

The Kigali amendment:

In the capital city of rwanda i.e. Kigali on 15 October 2016 the amendment was signed. HFCs are now used as the replacement of CFCs and HCFCs in the refrigeration and air conditioning since these both chemical are in the category of ODS also HCFCs are major green housegases. 

HFCs are not the ODS but their global warming potential may vary upto 14000 times the GWP of carbon dioxide. Keeping the amount of HFCs are released into the atmosphere it can be concluded that the average global temperature of the earth may increased by 2℃. So strong action is needed against these green house gases, The goal is to achieve over 85% reduction in HFCs consumption and production by the year 2047. The impact of amendment will avoid up to 0.5% increase in average global temperature by the end of this century.

Earth's Ozone Layer healing because of the worldwide Lockdown. And this is good for humanity.

More Articles:

Global Warming | Climate change | Weather Vs Climate | Impacts of Global warming

Engineering Drawing Tool Kit

Engine knocking and Detonation nicely explained