Earth's Atmospheric Composition Diagram

Diagram illustrating relative abundances of gases in Earth's atmosphere

Randy Russell, UCAR SciEd

This diagram shows the relative abundances of the main gases in Earth's atmosphere. Nitrogen makes up 78%, oxygen about 21% and argon almost 1%. Lesser constituents include carbon dioxide at 400 parts per million (0.04%) and everything else (neon, helium, methane, krypton, hydrogen, etc.) at less than 28 parts per million combined.