The UV radiations directly reach the Earth’s surface, which may be dangerous to living beings due to the associated skin problems.   

Over the past decades, each passing day had created increasing awareness of the importance of balanced environment. It is crucial in sustaining the prevalence of life on the Earth. The Earth is covered by a blanket of ozone layer that comprises of critical gases present in the atmosphere. Ozone is made up of three atoms of oxygen, i.e. O3. Oxygen present in the atmosphere is split into single atoms due to sunlight. On the other hand chemical reactions occur in the upper layers of atmosphere. These single atoms either form oxygen (O2) or may form Ozone (O3). Sometimes single oxygen atom can react with oxygen to form ozone, as shown in the Fig.1.  

ozone formation

Ozone layer is present in the stratosphere and between 10 km to 50 km above the surface of the Earth. Stratosphere consists of 90% of total ozone on the planet. The dimensions of this layer can be measured in Dobson Unit (DU). Ozone layer has average thickness of 300 DU, that is 3 millimetres. This thin layer absorbs the strong harmful Ultraviolet B radiation that travel to the Earth from the cosmic surroundings. It also absorbs pollutants from the atmosphere. Ozone is also present at the ground level. The chemical reactions between the pollutants from exhaust gases of the vehicle, gasoline vapours and other emissions form ozone gas. Although useful, by itself the ozone is harmful, as it causes throat and lung irritation or aggravation of asthma or emphysema. 

ozone layer

Importance of Ozone Layer Prevention:

Since the past several decades, the ozone layer is dwindling each year. In addition, the chemical reactions of ozone with chlorine and bromine can cause its degradation. This leads to the formation of pockets in this layer. This is known as the ‘ozone hole’. As a result, the UV radiations directly reach the Earth’s surface. This might be dangerous to living beings due to the associated skin problems such as cancer.   

Industrial products, including Chlorofluorocarbons (CFC), aerosols, and carbon tetrachlorides such as medical products, tobacco, cancer therapeutics and also agricultural and pharmaceutical chemicals, foams, halons, methyl bromide, solvents, coatings, and adhesives are substances responsible for the depletion of the ozone layer. 

Scientific studies and proofs have lead to the Montreal protocol, which was signed by 28 countries on March 22, 1985 at the Vienna Convention for the protection of the ozone layer. The protocol aims at preserving the ozone layer by controlling not only the total global production but also consumption of substances that deplete it. The other way round with the ultimate objective of eliminating its depletion is through developing the scientific knowledge and technologies. Later in 1994, the United Nations General Assembly publicly declared September 16 as the international day for the preservation of the ozone layer. It has thus become our moral duty to be aware of the constituents of the products that we use. We should know their consequences on the environment. These are essential steps to preserve our Earth for the health and existence of our future generations.

Editor: Dr. Prajakta Dandekar-Jain

Image resources:

  1. https://www.geo.arizona.edu/Antevs/nats104/00lect28.html

References:

  1. http://sdg.iisd.org/events/international-day-for-the-preservation-of-the-ozone-layer-2019
  2. https://en.wikipedia.org/wiki/International_Day_for_the_Preservation_of_the_Ozone_Layer
  3. https://www.un.org/en/events/ozoneday/
  4. https://www.un.org/en/events/ozoneday/ozonescience.shtml
  5. https://www.unenvironment.org/ozonaction/
  6. https://www.unenvironment.org/news-and-stories/story/keep-cool-and-carry-protecting-our-ozone-layer-and-climate-world-ozone-day

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