Science Articles

Everything You Need To Know About The Ozone Layer

The ozone layer or ozone shield is a region of Earth’s stratosphere that absorbs most of the Sun’s ultraviolet (UV) radiation. It contains high concentrations of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere.

You know that the Earth is surrounded by a layer of atmosphere that protects us from the harmful ultraviolet rays of the Sun. You must have also heard about something called the ‘Ozone Layer’. However, do you know what exactly the ozone layer is all about?

Well, just as global warming and greenhouse gases have been cause for concern, so also the depleting ozone layer has been causing a lot of heart-burn among environmental scientists.

However, not everyone is aware about this very important layer of our atmosphere.So, let us understand a few things about the ozone layer-


What Is The Ozone Layer?

The earth’s atmosphere is divided into several layers. The layer of atmosphere that is present from the surface of the earth till about 12 km above the surface is called the Troposphere. From 12 to 50 km is the Stratosphere, from 50 to 80 km is the Mesosphere,from 80 to 700 km is the Thermosphere and from 700 to 10,000 km is the Exosphere.

The lower part of the stratosphere, from 20 to 30 km above the earth’s surface, is made up of a layer of special molecules called ozone molecules. This layer in the stratosphere consists of a high concentration of ozone molecules and hence is called the ozone layer.


Why Is The Ozone Layer Special?

The ozone layer was discovered in 1913 by French physicists Charles Fabry and Henri Buisson. The reason why it is so special is that the ozone layer absorbs almost 97 to 99 percent of the Sun’s medium-frequency ultraviolet light.

This ultraviolet radiation is extremely harmful for all living organisms, as it can damage the DNA of living beings, cause skin cancer, cataracts and genetic damage, and play havoc with our immune systems.

The ozone layer absorbs this harmful solar radiation, thus protecting life forms on earth and allowing them to flourish and thrive. It is thus an extremely vital and critical component of the earth’s atmosphere.

If there was no ozone layer, no life forms on earth could have survived the heat and radiation of the Sun. Yes, that’s how crucial it is to earth and earthlings!


How Is The Ozone Layer Formed?

Ozone is an element synthesised in nature.One molecule of ozone contains three atoms of oxygen. An oxygen molecule, on the other hand, is made up of two atoms of oxygen. Since the ozone layer protects the earth from the ultraviolet radiation coming from the Sun, it is ironic that these very ultraviolet rays are the reason for the synthesis of ozone molecules.

When the ultraviolet rays strike the oxygen molecules present in the stratosphere, the oxygen molecules split up into individual oxygen atoms, forming atomic oxygen. Each individual oxygen atom then combines with unbroken to create ozone,.This process goes on continuously within the atmosphere, and is known as the ozone-oxygen cycle.

About 90% of atmospheric ozone is contained in the Stratosphere.


Ozone Depletion- Cause For Concern

The ozone layer, as vital as it is to the Earth’s biological environment, has been depleting at an alarming rate in recent times. This simply means that the layer of ozone in the atmosphere is thinning rapidly. In 1987, a hole, the size of the USA, was observed in the ozone layer above Antarctica.

This depletion in the ozone layer is the result of the release of harmful compounds called Chlorofluorocarbons (CFCs) into the atmosphere. These CFCs are used in refrigeration, cold storage plants and manufacture of aerosols. These CFCs, when released, drift up to the stratosphere and break up into chlorine and other atoms. The chlorine reacts with the ozone, breaking down the ozone molecules. Scientists estimate that just one atom of chlorine can destroy one million ozone molecules. This continuous process causes depletion of the ozone layer.


Concrete steps have now been taken to stem the depletion of the ozone layer, most of which have been extremely successful in the release of harmful chlorine atoms. But, more on that in another article!