Air is a mixture composed of several gases, primarily dinitrogen N2 (approximately 80 %) and dioxygen O2 (approximately 20 %).
| Dinitrogen
Formula: N2 Proportion: 78.08 % |
| Dioxygen
Formula: O2 Proportion: 20.95 % |
| Argon
Symbol: Ar Proportion: 0.934 % |
| Carbon dioxide
Formula: CO2 Proportion: 0.0382 % |
| Neon
Symbol: Ne Proportion: 0.001818 % |
| Helium
Symbol: He Proportion: 0.000524 % |
| Nitric oxide
Formula: NO Proportion: 0.0005 % |
| Krypton
Symbol: Kr Proportion: 0.000114 % |
| Methane
Formula: CH4 Proportion: 0.00017 % |
| Dihydrogen
Formula: H2 Proportion: 0.00005 % |
| Nitrous oxide
Formula: N2O Proportion: 0.00005 % |
| Xenon
Symbol: Xe Proportion: 0.0000087 % |
| Nitrogen dioxide
Formula: NO2 Proportion: 0.000002 % |
| Ozone
Formula: O3 Proportion: 0 - 0.000001 % |
| Radon
Symbol: Rn Proportion: 6 × 10-18 % |