Composition Of Air: Presence Of Different Gases You Didn’t Know Of

We are surrounded by air. It is everywhere, and the air we breathe is more than it seems. There are different layers of air, and each layer has different characteristics. 

Air is vital for sustaining life. It is like a blanket of gases that is important for several metabolic functions. It is essential because it protects us from heat blasts and radiation. Air also heats up and cools the environment around us. 

According to NASA, the gases in the earth’s atmosphere are nitrogen, oxygen, and carbon dioxide. It also has helium, methane, hydrogen, krypton, and a small amount of water vapour. 

Joseph Priestley discovered the composition of air, and several other investigators like Henry Cavendish showed how air is a mixture of several gases. 

Read to know more about the composition of air

Major components

  • A significant component of air is nitrogen which amounts to 78%, followed by oxygen which is 21%, followed by argon which is 0.93 %. 
  • Carbon dioxide, which is very important for plants, makes up only 0.04% of the air. The air is also composed of other gases in trace amounts, including neon helium, methane, and water vapour.
  • Air is crucial for life, and these important components shape the quality of air. Apart from that, breathing air has a critical role. 
  • It contributes to the abiotic components of the environment. 
  • It is also essential for the water and nitrogen cycle. 
  • It forms an integral part of the atmosphere.

Chemical composition

Air is a homogeneous mixture of different gases. These gases have colourless and odourless properties. It is difficult to separate them by the naked eye. 

The composition mentioned above is 78% nitrogen 21%, Oxygen 1% and other gases. Water vapour is an essential part of the air you breathe, but these other trace gases also shape the chemical composition of air.

It is necessary to know that air’s chemical composition changes from place to place, depending on moisture content and temperature. 

Variations in the air

  • The water vapour present in the air depends on the carrying capacity of the air. This is shaped by temperature. The composition also changes with elevation, and this happens at the height of approximately 10.000 m. 
  • Air composition also changes with temperature, and it changes at the rate of 0.6 degrees Celsius for every hundred-metre increase in the vertical height. 
  • The pressure of air is 1 standard atmosphere which is the pressure that is equal to the pressure that is exerted by the 760 mm column of Mercury at this temperature. This is recorded at zero degree celsius sea level, and the standard gravity at this moment is 32.17 feet/second square. 

Other minor components of air are sulphur dioxide, methane, nitrous oxide, ozone, nitrogen oxide, iodine, carbon monoxide and ammonia. These are all homogenous in air and cannot be differentiated by the naked eye.

Properties of air

Air is colourless and odourless.

The air that we breathe is colourless and odourless. It cannot be seen but can be felt because of the movement.

Air takes space

Air is a mixture of different types of gases, and it has the property of occupying space. Thus it has a volume, but it does not have a specific shape.

Air exerts pressure

Air exerts pressure. This pressure is called air pressure because of the existing weight. Air has gravity, and it has been seen that the mixture of gases is always denser near the surface than at a higher altitude.

Expansion properties

Air also has properties of expansion. This means it expands and takes more space when it is heated. The density also becomes less, and it becomes thinner. This can be seen when the warm wind has a lower pressure than the cold wind. 

Component wise description of air


The major component of air is nitrogen, the most abundant gas on Earth. This plays a significant role in the nitrogen cycle and other functions. This is important for metabolic growth. Nitrogen contributes to biodiversity.  It is also an essential part of fertilisers essential for the growth of crops. Nitrogen is a prominent inhibitor of combustion.


Air contains 21% oxygen. Oxygen is a vital gas for supporting life. It is essential for several metabolic functions- existing and for energy needs. Respiration involves breathing oxygen, using it to make energy and subsequently, the gas exchange, releasing carbon dioxide. Oxygen is a promoter of combustion, and it is used during composition and carbon dioxide is formed as a byproduct. 

Carbon dioxide 

Carbon dioxide forms a tiny percentage of air, but it is essential for plants and animals. The primary use of carbon dioxide is for synthesising food during the process of photosynthesis. It is also known for its warming effect. 

This means it is a greenhouse gas and maintains a comfortable temperature. High levels of carbon dioxide in air areas are highly polluted. Thus, it is a vital gas for survival.

Water vapour

Air also contains water vapour in small amounts. This is formed because of water’s evaporation, which rises due to the heat and then mixes with the atmosphere. The presence of this evaporated water in the air is essential for the functioning of life and the movement of the water cycle. Water vapour in the air is high in highly humid places. 

Smoke and dust particles

Air also contains varying amounts of smoke and dust particles. This accumulates in the air because of emissions, and the composition changes from site to site. Highly polluted areas have a higher composition of smoke and dust.

Other essential components are found in trace amounts of air hydrogen-helium, ozone, methane, Krypton, etc. They performed their roles in the environment.

Summing it up

Air is essential for the formation of the atmosphere. The atmosphere is composed of air which acts as a blanket of gases to protect life on earth. Thus, being aware of air composition helps in better understanding of factors affecting it. We covered different gases in the air and their composition in detail and how it affects the atmosphere we breathe in.

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