Ozone Layer, the life protective cover of the Earth

The ozone layer was discovered by the French physicists Charles Fabry and Henri Buisson in 1913. This life protective ozone layer contains a high concentration of Ozone (O3) in relation to other parts of the atmosphere. This region of the upper atmosphere between roughly 15 km and 35 km above Earth’s surface also called ozonosphere. Though Ozone is harmful at ground level, ozone layer in higher atmosphere plays a vital role in the protection of all living beings. 

Importance of Ozone Layer

Ozone Layer protects the Earth and its inhabitants as follows

• The main function of the ozone layer is protecting the Earth from the UVB Radiation of Sun. It prevents the exposure to ultraviolet radiation which can increase the risk of detrimental effects such as cataracts, skin cancer and other harmful effects such as compromised immune systems among humans.
• Ozone layer prevents negative UV radiation effects on the developmental processes of plants through screening process. In the absence of this process, UV rays also affect plant growth, reducing agricultural productivity. Thus Ozone layer stabilizers global food production indirectly.
• Ozone layer which occupies the lower part of the atmosphere removes the unwanted pollutants from the earth’s surface gifting healthy environment.
• Ozone layer may also important in controlling wind patterns which effects on climatic conditions and helps to mitigate global warming.

Depletion of Ozone Layer

Ozone depletion is the process of gradual thinning of Earth’s ozone layer in the upper atmosphere, caused by the release of chemical compounds containing gaseous Chlorine or Bromine; emitted  due to anthropogenic activities such as industrial and agricultural operations. In addition to anthropogenic activities, natural causes such as Sun-spots and stratospheric winds are responsible for the depletion of the Ozone; however it does not cause more than 1-2% of the ozone layer depletion. Ozone depletion consists of two related events as a steady lowering of ozone in Earth's atmosphere (the ozone layer) about 4% in the total amount and a much larger springtime decrease in stratospheric ozone around Earth's polar regions (the ozone hole). The thinning process is most pronounced in the Polar Regions, especially over Antarctica.

Ozone-depleting substances (ODSs) 

Ozone-depleting substances are the main cause of thinning of ozone layer and the making the ozone hole. Once released, ozone-depleting substances stay in the atmosphere for many years and continue to cause damage. Therefore, the ozone layer is not expected to recover fully before the second half of this century.

A list of some main ozone-depleting substances and the sources from where they are released are as follows:

Detrimental effects of Ozone depletion

• Depletion of Ozone layer and expanding of ozone hole is a current environmental issue. Due to the detrimental effects of UVB radiation ill health conditions such as skin cancer, damage to skin cells, ageing of skin, sunburn, permanent blindness, snow blindness, cataracts and damage to DNA and leads to mutation, were projected to increase dramatically as a result of thinning Ozone layer, and increased surface UV leads to increased tropospheric ozone and it is a health risk to humans.
   
• Ozone depletion effects on animals too. Aquatic animals such as whales and many other terrestrial animals including dogs, cats, sheep and terrestrial ecosystems are also suffering from the negative effects of increased UV-B radiations.
   
• Due to depletion of Ozone layer plants receive UV-B rays and mean smaller leaf size, decreased plant growth and results lower quality crops for humans. 
   
• Increases in UV-B rays greatly effects on Phytoplankton and zooplankton since they are very sensitive to the amount of light in their environment.

Anthropogenic activities responsible for the depletion of the ozone layer

The main anthropogenic activities responsible for the depletion of the ozone layer are as follows;

•  Use of Chlorofluorocarbons
•  Launching of unregulated Rockets
•  Emissions of Nitrogenous Compounds (NOx) such as NO2, NO, N2O

International agreements for protecting the Ozone Layer.

The major international agreements on the protection of Ozone Layer are as follows.

• Montreal Protocol on Ozone Layer depletion

The Montreal Protocol, the main international treaty has been designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion and it regulates the consumption of ODSs as well. The Montreal Protocol was adopted on September 15th, in 1987.

• EU regulation

EU legislation on ozone-depleting substances is among the strictest and most advanced in the world and it provides the legal basis for the protection of the ozone layer within the European Union.

• The Vienna Convention for the Protection of the Ozone Layer

The Vienna Convention was adopted in 1985 is the precursor to the Montreal Protocol and is often called a framework convention, because it served as a framework for efforts to protect the ozone layer.

International Day for the Preservation of the Ozone Layer

Commemorating the date of the signing of the Montreal Protocol in 1987 on Substances that deplete the Ozone Layer, 16th of September was proclaimed as the “International Day for the Preservation of the Ozone Layer” at the United Nations General Assembly held in 1994.

To join the with the ideas and seminars on protection of Ozone Layer, people from all over the world are expected to gather in Montreal on September 16th. This International Day is mainly intended to spread awareness of the depletion of the Ozone Layer and search for solutions to preserve it.

Under the global pandemic situation of COVID-19, World Ozone Day to be marked on 16th September in 2021, under the theme "Montreal Protocol - Keeping us, our food and vaccines cool".

International initiatives and the collective efforts to protect the ozone layer are as follows.

• Ensure to implement the existing restrictions on ozone-depleting substances properly and continue to reduce the global use of ODSs. Avoid or prevent from the activities related to Ozone Layer Depletion as a globe.
   
• Ensure the safe handling of ODSs
   
• Ensure the permitted uses of ODSs and are not been diverted to illegal uses.
   
• Reduce / avoid the consumption of ODSs in applications that are not considered under the Montreal Protocol.
   
• Ensure not to emerge new chemicals or technologies that could be posed new threats to the Ozone layer which have not been mentioned earlier.

Behavioral adaptations to be practiced in preventing depletion of ozone layer are as follows:

1, Avoid Using ODSs and replacing them using halon based fire extinguishers etc…..

2. Minimize the single Use of Vehicles and promote public transportation since the vehicles emit a large amount of greenhouse gases that lead to global warming as well as ozone depletion.

3. Use Eco-friendly cleaning products and these should be substituted with natural products to protect the environment.

4. Prohibit the Use of harmful Nitrous Oxide that adversely effect on the Ozone layer.

As individuals we can contribute to protect Ozone layer through conserving environment with planting trees and doing other eco-friendly activities such as use of eco-friendly products, preventing from open-burning of Polythene and Plastics etc… Let’s join together to protect Ozone layer under the blue sky through a sustainable strategy.

Information Sources - Internet (Kindly acknowledged)

N.M.L.Radhika

Assistant Director,

Environmental Education and Awareness Division,

Central Environmental Authority