词条	Average Composition of the Atmosphere
释义	Average Composition of the Atmosphere Table Average composition of the atmosphere gas composition by volume (ppm)* composition by weight (ppm)* total mass (1020 g) nitrogen 780,900 755,100 38.648 oxygen 209,500 231,500 11.841 argon 9,300 12,800 0.655 carbon dioxide 386 591 0.0299 neon 18 12.5 0.000636 helium 5.2 0.72 0.000037 methane 1.5 0.94 0.000043 krypton 1.0 2.9 0.000146 nitrous oxide 0.5 0.8 0.000040 hydrogen 0.5 0.035 0.000002 ozone** 0.4 0.7 0.000035 xenon 0.08 0.36 0.000018 *ppm = parts per million. **Variable, increases with height. See as table:
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