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Composition of the Earth's Atmosphere
Source: Definition of the U.S. Standard Atmosphere (1976)
CRC Handbook of Chemistry and Physics, 77th Edition
| Gas | Formula | Abundance percent by volume | Abundance parts per million by volume |
| Nitrogen | N2 | 78.084% | 780,840 |
| Oxygen | O2 | 20.9476% | 209,476 |
| Argon | Ar | 0.934% | 9,340 |
| Carbon Dioxide | CO2 | 0.0314% | 314 |
| Neon | Ne | 0.001818% | 18.18 |
| Helium | He | 0.000524% | 5.24 |
| Methane | CH4 | 0.0002% | 2 |
| Krypton | Kr | 0.000114% | 1.14 |
| Hydrogen | H2 | 0.00005% | 0.5 |
| Xenon | Xe | 0.0000087% | 0.087 |
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