What is Air?

Air is not a factor, is a mixture of different elements and gaseous compounds. At atmospheric pressure and temperature, the air exists as an odorless, colorless and tasteless.

The composition of dry air at standard conditions at sea level shown in the table below. There are other impurities that may vary geographically, but generally not considered as part of its composition.


Component Chemical symbol % By Volume
Nitrogen N2 78.084
Oxygen 02 20.946
Argon Ar 0.946
Carbon dioxide CO2 0.0335
Neon Ne 0.001818
Helium He 0.000524
Methane CH4 0.0002
krypton Kr 0.000114
Nitrous oxide N2O 0.00003
Xenon Xe 0.00000087

Nitrogen and oxygen in addition to more than 99% of compounds that make the air. The sum of the other gases mentioned are less than 1%.

Of all the components that make air, only oxygen and nitrogen are required to sustain life.

Oxygen content of the air is necessary to support the metabolic processes that our body uses to convert food into energy and heat. The average person consumes about 0.75 m3 of oxygen every 24 hrs, which is approximately 1.13kg. Surprisingly, it is about the same mass as the average person consumes in food per day.

Nitrogen content in the air breathed has no metabolic function. It serves only as an inert diluent in order to have our lungs mechanically pressurized.