Which element is the most abundant gas in Earth's atmosphere?

Which element is the most abundant gas in Earth’s atmosphere? The answer is nitrogen. Dry air contains about 78.08% nitrogen by volume, making it far more abundant than oxygen, argon, or carbon dioxide.

Atmospheric nitrogen is mainly present as N₂, a molecule made of two nitrogen atoms joined by a strong triple bond. That bond makes nitrogen relatively unreactive, helping it act as a stable background gas while oxygen supports combustion and respiration.

Nitrogen is essential to life because it forms part of amino acids, proteins, and DNA. Most organisms cannot use atmospheric N₂ directly; specialized bacteria convert it into biologically useful compounds through nitrogen fixation. Plants then obtain nitrogen through soil nutrients and pass it through food webs.

Nitrogen was recognized as a distinct component of air in the 18th century. Oxygen makes up about 20.95% of dry air, while argon contributes roughly 0.93%. Water vapor varies by location but normally remains far below nitrogen’s global share.