Composition of Air
The matter is anything that occupies space. Air is a matter which is inevitable in our lives. The earth is covered with a blanket of air called the atmosphere. Among the few fundamental elements, it is the most important because no life can exist for a pulse of time without it. It is needed by every single organism for their survival. In addition to breathing, it has an influential role on abiotic components of environment like wind, rain, climate, etc.
We often take air as a single unit. In reality, air is composed of several gases. The composition of air consists of three key components of air, namely Nitrogen (78%), Oxygen (21%), Argon (1%), Carbon-di-oxide (0.03%) and water vapor. Air also has some other gases but they are in very minute percentage.
It is also important to understand that the composition stated above is the ideal composition of air, which maintains the fine balance in nature. In places where this composition of air varies, the atmospheric balance of nature may be tilted. For instance, in an industrial area, the composition of air can differ drastically. There may be a high quantity of harmful gases emitted from the industrial chimneys that can increase the amount of carbon-dioxide in the air, making it harmful to anyone who breathes such air.
The most important gas in the composition is oxygen. Oxygen is an important gas, both for humans as well as the atmosphere. It supports in breathing for living beings, but at the same time, oxygen is a combustible gas, which means, it can catch fire quickly. Thus, when you light a candle, it easily lights up. Try doing the same in a vacuum, and you will not be able to light it. Which means air consists of combustible substance too. This is why the composition of oxygen in the air is just about 21%. Just enough to give us healthy lungs, but not enough to start a random fire!
To balance out oxygen, there is Nitrogen. It is a non-combustible gas and occupies the highest percentage of air. This is why, when you blow on a candle it is easily extinguished. This is done because of the presence of nitrogen. Nitrogen is also one of the most abundantly found gases on earth.
Presence of Argon in the air was first suspected by Henry Cavendish in 1785, but it was not confirmed until 1894 when Lord Rayleigh and Sir William Ramsay attested to it. This gas is known to occur naturally in the environment and easily dissipates in a well-ventilated space. In itself, argon is an asphyxiant and inhalation of it can lead to dizziness and nausea in a person.
Carbon dioxide is infused in the air due to respiration. Living beings inhale oxygen and exhale carbon dioxide. There are other ways by which carbon dioxide is infused in the atmosphere, and its composition keeps changing depending on the place where you are. In general, it should occupy about 0.38% of the earth’s total atmosphere.
Finally, we have water vapor. When the water present in the water bodies evaporates due to heat, it rises up and mixes into the atmosphere. You can assess the presence of water vapor in the air by measuring the humidity level. You will notice that as we come closer to sea, the level of humidity rises. This is because the amount of water vapor is more near seaside areas.