What is the Ozone Layer?

OZONE LAYER: THE SHIELD OF THE EARTH

In this article, we will particularly talk about the protective shield of the Erath, Ozone Layer. We have provided detailed information about the topic starting from what is the Ozone layer, its properties, formation, importance to its depletion and the consequences.

What is the Ozone layer?

The Ozone layer is a protective shield around the earth’s surface which is present in the stratosphere approximately 15-30 kilometres above the Earth’s surface.

The layer functions by absorbing the harmful ultraviolet radiations of the Sun. Also, it prevents them from reaching the Earth’s surface. It is formed of a high and dense concentration of ozone molecules.

The Ozone layer is often referred to as the ozonosphere. It is present in the upper atmosphere which extends from approximately 10-15 kilometres. It can even span up to 50 kilometres.

What are the properties of the Ozone layer?

Ozone gas which forms the ozone layer consists of three oxygen atoms and is often referred to as trioxygen.

Ozone properties can be further classified into – Physical properties and Chemical properties

Ozone Layer

Physical properties

  • Ozone is a coloured gas of blue colour
  • It has a boiling point of -112° Celsius and freezing point of -192.2° Celsius
  • Ozone is a dipolar molecule and electrophilic and reacts very selectively
  • Ozone partially dissolves in water at atmospheric pressure
  • As compared to oxygen, ozone has the thrice its solubility
  • Atomic weight – 48
  • Density – 2.12 kg O₃/ m³ Bij 0 °C 1013 mbar
  • Electrochemical potential – 2.07 volt
  • Ozone occurs bluish in the gaseous state and dark blue in a fluid state

Chemical properties of the Ozone layer

  • Ozone in its gaseous states has a pungent and acrid smell
  • It has a cylindrical structure with its oxygen atoms at a distance of 1.26 Å
  • It has three oxygen atoms with a molecular weight of 48.00
  • Ozone is an unstable gas and decomposes at 573k instantaneously
  • Oxidizing agent – It is a powerful oxidizing agent
  • Reducing agent – It has reducing property as it reduces peroxide to oxide and getting reduced to oxygen
  • The moist starch-iodide paper test – Turns it blue

Distribution of the Ozone layer in the Stratosphere

Over 90% of the ozone present in the atmosphere is present above the troposphere. It is 9 km in the Polar Regions and 16-17 km in the tropic region above the earth’s surface.

The highest concentrations of ozone are found between 20-30 kilometres above the earth’s surface and 10 kilometres above the tropopause.

The concentration and distribution of the ozone vary with the seasons as well. The highest concentrations are reported in the mid to late winters in the northern regions and Polar Regions.

High ozone concentrations in winter lead to cold surface temperatures.

What is the importance of the Ozone Layer?

Ozone holds immense importance for the earth and humans. It prevents most of the harmful UV radiations to reach the earth’s surface by absorbing them.

Moreover, his regulates the earth’s temperature by keeping the ultraviolet rays away from the inhibited surroundings.

Above all, UV rays can be harmful to humans, plants, animals and surroundings and the ozone layers protect the ecosystem by absorbing them.

Life without ozone on the earth would be difficult and dangerous. Also, it reflects the ultraviolet rays back into space to a certain extent.

What is the Ozone layer depletion?

Ozone layer depletion refers to the breaking down of the ozone molecules which leads to the thinning of the ozone layer in the stratosphere.

In other words, when the number of ozone molecules is reduced or wears out due to harmful chemicals such as chlorine, they layer of ozone present in the atmosphere thins causing the harmful ultraviolet radiations of the sun to enter the Earth’s surface.

What causes the Ozone layer depletion?

Ozone layer depletion is significantly caused by human activities which involve emission of human-made chemical that contains chlorine or bromine.

When contacted with the ozone particles, chlorine and bromine eradicate an atom from the ozone molecule.

They are so dangerous that even one chlorine atom can successfully break down thousands of ozone molecules.

Chlorofluorocarbons are the chief reason behind the depletion. They are used by various things of daily use such as soap, refrigerators, insulating foams, aerosol sprays and air conditioners.

What are the effects of Ozone Layer Depletion?

The harmful UV-A, UV-B and UV-C rays have adverse effects when directly exposed to. They affect humans, plants, marine life, biogeochemical changes and materials as well.

  • Increased chances of the harmful UV-B radiations to reach the Earth’s surface which disrupts biological processes and damages various materials
  • Prolonged exposure to the harmful radiations, if reached the Earth’s surface can lead to various skin problems including cancer
  • The human immune system is impacted and premature skin ageing can be experienced
  • Direct UV rays affect plant growth and their physiological processes
  • The dangerous UV-B rays reduce phytoplankton production and decrease orientation and motility
  •  UV-B rays can affect various synthetics, polymer and biopolymer materials by reducing or limiting their useful lifespan.

What is the Montreal Protocol of the Ozone layer?

Signed on 16 September 1987, the Montreal Protocol is an international agreement developed with the purpose to protect the depletion of the Ozone layer.

The agreement deliberates about regulating the production of substances which are known to be Ozone-depleting substances (ODS).

The treaty also aims to regulate and reduce ODS consumption which damage the ozone layer when released in the atmosphere.

The protocol establishes the responsibility of all 197 UN Member States to act as per the agreement.

Montreal Protocol was fabricated around several man-made chemicals that are grouped as halogenated hydrocarbons. The chemical substances which the treaty regulates contain one of chlorine or bromine.

From the date when the Protocol came into effect, the concentration of CFCs and chlorine or bromine hydrocarbons have been decreased or levelled off to a certain extent.

Why is the Montreal Protocol important?

The Montreal protocol holds immense significance in recognizing the ODCs as the leading cause of ozone layer depletion. It determined and acted on the treat that followed and depletion and developed strict measures for it.

Owing to the implications of the treaty, the ODCs emission and production has been regulated.

The ozone layer has started to recover and is expected to recover as the 1970s by the 2050s or 2060s.

What is the current buzz about the Ozone layer?

Amidst the COVID-19 (novel coronavirus) pandemic, there is some good news for the ozone layer.

Lockdowns in various countries around the world halted the processes of industries which dealt in harmful chemicals, responsible for ozone layer depletion.

Emissions have drastically decreased worldwide due to limited economic activities and industrial working.

According to New Scientist, the hole in the layer above the Antarctica region has witnessed accelerated recovery while changing the atmospheric circulations.

As the hole over the Antarctica region heals, it has lead to reversing the changes caused to the wind flows due to ozone layer depletion in the southern hemisphere.

The ozone layer is significant for the environment and well-being of the human race. The shield of the planet has begun to recover and is good for the future.

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