Table 3.1.
Global average concentration of well mixed atmospheric constituents.a
| Compounds | Formula | Concentration | Total mass (g) |
|---|---|---|---|
| Major constituents (%) | |||
| Nitrogen | N2 | 78.084 | 3.87 × 1021 |
| Oxygen | O2 | 20.946 | 1.19 × 1021 |
| Argon | Ar | 0.934 | 6.59 × 1019 |
| Parts-per-million constituents (ppm = 10− 6or μL/L) | |||
| Carbon dioxide | CO2 | 400 | 3.11 × 1018 |
| Neon | Ne | 18.2 | 6.49 × 1016 |
| Helium | He | 5.24 | 3.70 × 1015 |
| Methane | CH4 | 1.83 | 5.19 × 1015 |
| Krypton | Kr | 1.14 | 1.69 × 1016 |
| Parts-per-billion constituents (ppb = 10− 9or nL/L) | |||
| Hydrogen | H2 | 510 | 1.82 × 1014 |
| Nitrous oxide | N2O | 320 | 2.49 × 1013 |
| Xenon | Xe | 87 | 2.02 × 1015 |
| Parts-per-trillion constituents (ppt = 10− 12) | |||
| Carbonyl sulfide | COS | 500 | 5.30 × 1012 |
| Chlorofluorocarbons | |||
| CFC 11 | CCl3F | 280 | 6.79 × 1012 |
| CFC 12 | CCl2F2 | 550 | 3.12 × 1013 |
| Methylchloride | CH3Cl | 620 | 5.53 × 1012 |
| Methylbromide | CH3Br | 11 | 1.84 × 1011 |
a
Those with a mean residence time > 1 year. Assuming a dry atmosphere with a molecular weight of 28.97, the overall mass of the atmosphere sums to 514 × 1019 g.
Source: Updated from Trenberth and Guillemot (1994).