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Last updated date: 24th May 2024
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What is Air?

Everything that takes up space is classified as matter. Air is unavoidable for our existence. The atmosphere is a blanket of air that covers the world. It is among the most vital elements for the existence of life since no life can survive for a single pulse of time without it. It is necessary for all creatures to survive. Let us learn about “what is air made of” and air composition. Also, air influences abiotic environmental components such as wind, rain, and climate.

The atmosphere, usually known as air, is a combination of different gases. When we think of air, the first thing that comes to mind is oxygen, which is necessary for life on earth to survive. However, oxygen is not the only important gas present in the air. Other gases are equally crucial in the maintenance of life. Let's take a closer look at the composition of the air that allows life to exist on earth.

Air Composition in Atmosphere

The atmosphere of the Earth is made up of a combination of gases called air. These gases are colourless and odourless. In the atmosphere, these gases combine to form a mixture of gases. It is made up of 78 % nitrogen, 21% oxygen, and 1 % other gases and water vapour. As we move up through the levels of the atmosphere, the composition of the air does not change. The number of molecules present in the air is what changes. The number of air molecules decreases and becomes smaller, as we go up. The moisture content varies from location to location. As compared to wetlands, arid places have less moisture content. The amount of water vapour or moisture in the air fluctuates. Air's maximum moisture carrying capacity is primarily determined by temperature. Until you reach a height of around 10,000 m, the composition of the air remains unchanged.

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Percentage of Gases in Air

Nitrogen is the most abundant naturally occurring gas, accounting for approximately 78% of air. With a prevalence of roughly 21%, oxygen is the second most abundant gas in the air. Argon, an inert gas, accounts for 0.93 % of the total composition. The atmosphere contains trace amounts of carbon dioxide, neon, helium, methane, krypton, hydrogen, nitrous oxide, xenon, ozone, iodine, carbon monoxide, water vapours, and ammonia. Now, let us talk about how these gases are produced and their various roles in our environment.

  • Nitrogen: Nitrogen makes up 78% of the air in the atmosphere. The nitrogen cycle transfers nitrogen to plants, animals, and the environment.

  • Nitrous Oxides: When nitrogen oxides interact with water droplets in the air, they produce nitric acid, which contributes to acid rain.

  • Oxygen: Oxygen accounts for 21% of the atmosphere. It is extremely reactive and forms compounds with a wide range of other chemicals, and it is required for living creatures to breathe.

  • Ozone: The ozone layer, formed by ozone gas in the stratosphere, is critical for the survival of life on Earth's surface.

  • Argon: Argon makes up around 1% of the atmosphere and is mostly produced by the breakdown of potassium in the Earth's crust. It does not react with other substances since it is an inert gas.

  • Water Vapours: Water circulates through all of Earth's systems in its three states, solid, liquid, and gas. Since it can trap heat, water vapour in the atmosphere acts as a greenhouse gas.

  • Carbon Dioxide: Carbon dioxide makes up about 0.03 % of the atmosphere naturally, but it is growing as a result of the combustion of fossil fuels. Carbon dioxide is used by plants and eubacteria during photosynthesis. Through breathing, humans, other animals, and plants contribute to the air. It is a heat-trapping greenhouse gas. 

  • Carbon Monoxide: Carbon monoxide in the atmosphere is caused by the combustion of gasoline in automobiles, volcanoes, and forest fires. It's a lethal gas.

  • Methane: Landfills, animals and their manure, and oil and gas wells, all emit methane gas into the atmosphere. It is also produced during the decomposition of organic matter. It is a heat-trapping greenhouse gas.

  • Sulphur Dioxide: When coal and oil are burnt, sulphur oxides are created. It is also emitted by volcanoes. Sulphuric acid is formed when sulphur oxides in the atmosphere react with water droplets. Sulphuric acid is a component of acid rain.

Various Properties of Air

As already stated, gases are matter. Gases, like every other matter, have particular features. The following are some examples of frequent properties.

  • Colourless and Odourless: Air is usually colourless and odourless. It's an impenetrable substance that can only be felt. All living things require oxygen to survive. Moving air is referred to as wind.

  • Occupy Space: It is a blend of many gases. As a result, they, like all matter, occupy space. A balloon expands when blown because the air poured into it fills the empty area. 

  • Exerts Pressure: It has weight, and air pressure is the force exerted by the weight of air. This combination of gases near the surface is denser than at high elevations due to gravity. That explains why the gaseous atmosphere is thinner in the mountains than at ground level.

  • Expansion: Another feature is its ability to grow. It expands and takes up more area when heated. As a result, the pressure of the warm wind is lower than that of cold wind.

FAQs on Air

1. What are the components of air?

The various components of air are nitrogen, oxygen, carbon dioxide, and other gases. Water vapour, trace gases such as argon, helium, hydrogen, smoke, dust particles, etc., are all part of it. The components of air change depending on location. For example, the air in mountains is thinner than on plains. This is why mountaineers usually bring oxygen cylinders with them. Furthermore, the proportion of oxygen in the air may be higher in locations with more flora. Due to the scarcity of water in desert locations, the water vapour content will be much lower than in typical places. 

2. What do you mean by air and write its various properties?

The invisible mixture of gases that surrounds the earth is known as air. Most organisms require vital elements found in air, such as oxygen and nitrogen, to thrive. Humans are, of course, one of those species. The term "atmosphere" is sometimes used instead of "air". It has various properties which are given below as:

  • It is colourless and odourless in nature.

  • It occupies the space around it.

  • Since it is a combination of various gases therefore it exerts pressure on its surroundings.

  • It also has the ability to expand upon heating.