On this page, we will discuss what Gas makes up most of the earth’s atmosphere. The atmosphere of Earth, commonly known as air, is the layer of gases retained by Earth’s gravity that surrounds the planet and forms its planetary atmosphere.
The most abundantly present gas in the atmosphere by far is nitrogen, which accounts for about 78% of the mass of dry air. While the second most abundant gas in the atmosphere is Oxygen, present at levels of 20 to 21%.
List of available gases in the atmosphere and their percentages
| Gas Name | Chemical Formula | Percent Volume |
| Nitrogen | N2 | 78.08% |
| Oxygen | O2 | 20.95% |
| *Water | H2O | 0 to 4% |
| Argon | Ar | 0.93% |
| *Carbon Dioxide | CO2 | 0.0360% |
| Neon | Ne | 0.0018% |
| Helium | He | 0.0005% |
| *Methane | CH4 | 0.00017% |
| Hydrogen | H2 | 0.00005% |
| *Nitrous Oxide | N2O | 0.00003% |
| *Ozone | O3 | 0.000004% |
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Sources
https://www.thoughtco.com/most-abundant-gas-in-the-earths-atmosphere-604006
https://kids.frontiersin.org/articles/10.3389/frym.2019.00041
http://tornado.sfsu.edu/geosciences/classes/m201/Atmosphere/AtmosphericComposition.html