Layers of Atmosphere and Importance of Air

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What is Air and Atmosphere?

Air is the constant pressure of gases, that we feel all around us but cannot see. Atmosphere, on the other hand, is the layer of gases all around the surface held by the gravitational force of the earth. Thus, air can be said to be a component of the atmospheric conditions and atmospheric pressure indicating that air and atmosphere are very closely related. The difference between air and atmosphere is the physical characteristic such as air being a pressure of gases and atmosphere being a mixture of gases. The oxygen gas which is responsible for all the living creatures on earth underlines the importance of air for a living being. The importance of atmosphere around Earth can be characterized by the possibility of life on earth in the current state which would not have been possible with the meteorite event and sun rays from the sun. 

Importance of Atmosphere and the Atmospheric Layers

From the introduction, it is clear that the atmosphere is a mixture of gases present around the surface of the earth due to its gravitational attraction. This mixture of gases can be divided into different layers depending on various factors. So, what are the five layers of the atmosphere? They are the following from top to bottom (near the surface): Exosphere, Thermosphere, Mesosphere, Stratosphere and Troposphere. These five different layers provide protection and also make life possible because of the constituent gases which state the significance and importance of atmosphere. The five layers provide a wide range of distribution of gases and the densities of the gases at each layer of the atmosphere. 

The five layers of the atmosphere and their composition and properties are explained below:


The exosphere is the outermost layer of the atmosphere. Its limits reach from around 700 km to 10,000 km from the surface of the earth. There is not much definite boundary between the vacuum of space and the exosphere, as the air gets thinner and thinner moving away from the surface of the Earth. It mostly consists of few particles that move to and from space.


It is the layer of the atmosphere ranging from 100 km to 700 km limit of the atmosphere. It begins at the Karman line and is the space where the space shuttles mostly revolve around the Earth. Even though the temperatures are high, the heat is not felt because of the low atmospheric pressure. The International Space Station also orbits around the Earth in this region.


This is the densest layer of atmosphere amongst the top three layers. Because of this density, this layer is responsible for the burning of the meteors and other objects falling from space due to the gravitational force of the Earth. Also, there is a temperature drop in this layer with temperatures reaching -110° C. The layer between the mesosphere and the stratosphere known as the mesopause is the coldest place on Earth. It expands from 50 km to 90 km above the earth’s surface.


This layer of atmosphere is right above the troposphere and is without any or much of the water vapour. This layer also consists of the ozone layer which is filled with ozone (O3) gas. As is well-known the main function of the ozone layer is to protect the earth from the harmful ultraviolet rays of the Sun. It ranges from 30 to 50 km above the surface of the earth. 


This is the last layer and the closest layer to the surface of the Earth. This layer reaches up to 39 km from the surface of the earth. It is the densest layer and is filled with many different gases. The most abundant gas is Nitrogen which comprises 78% of the component and Oxygen 21% with other gases taking up 0.9% argon and 0.04% carbon dioxide with small traces of other gases. 

The above-mentioned earth air layers also show the importance of atmosphere in the protection of the earth and their contribution to the possibility of life on Earth. The distribution of the layers of the atmosphere is given below in the diagram:

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Importance of Air

Air is the fundamental building block without which life would cease to exist as it is. All the organisms require oxygen present in the air for respiration and generating energy. It is utilised for the generation of energy by metabolism by the cells. The nitrogen is also utilised by the nitrogen-fixing bacteria for the growth of plants in a symbiotic relationship with the plants. The importance of air is also signified as it is responsible for many phenomena such as the scattering of light and the travelling of sound. 

As per the definition of Air, the pressure is because of the density of various gases present in the atmosphere. The pressure differences between different places lead to an increase in the flow of air and it is known as wind. The pressure difference is also a phenomenon of air and atmosphere which is responsible for rainfall. 


The given article briefly explains the difference between air and atmosphere and their definitions. It also underlines the importance of air and the importance of atmosphere. Thus, it can be concluded that without air and atmosphere life as we know it wouldn't have been possible on Earth. This is one of the most important differences between Earth and other planets for the existence of living organisms. 

FAQs (Frequently Asked Questions)

1. How Does Air Help Us in Daily Life?

Ans: Air is the primary requirement of all the living organisms on Earth. The oxygen present in the air is the most important element and supplier of energy for living organisms. Cellular respiration utilizes oxygen for the metabolic process and produces energy in the form of ATPs (Adenosine TriPhosphates) to carry out life processes.

2. What are the Uses of Atmosphere?

Ans: Atmosphere is the mixture of all the gases presents around the surface of the Earth because of its gravity. There are 5 different layers of the atmosphere which are: Exosphere, Thermosphere, Mesosphere, Stratosphere and Troposphere. All five layers have essential functions that contribute to the development of life on earth. For example, the ozone layer in the stratosphere stops the harmful ultraviolet rays from reaching the earth and the mesosphere is responsible for the burning of the meteors and other heavenly objects falling from space. 

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