Atmospheric composition upright=1.3|Visualisation of composition by volume of Earth's atmosphere. Water vapour is not included as it is highly variable. Each tiny cube (such as the one representing krypton) has one millionth of the volume of the entire block. Data is from NASA Langley.The composition of common nitrogen oxides in dry air vs. temperature.Chemical composition of atmosphere accordig to altitude. Axis: Altitude (km), Content of volume (\%). Average composition of dry atmosphere (mole fractions) Gas per NASA  Nitrogen, N2 78.084\%  Oxygen, O2 20.946\%  Minor constituents (mole fractions in ppm) Argon, Ar 9340 Carbon dioxide  , CO2 400   Neon, Ne 18.18  Helium, He 5.24 Methane  , CH4 1.7  Krypton, Kr 1.14  Hydrogen, H2 0.55  Nitrous oxide, N2O 0.5  Xenon, Xe 0.09  Nitrogen dioxide, NO2 0.02 Water Water vapour Highly variable;typically makes up about 1\% Notes: the concentration of CO2 and CH4 vary by season and location. The mean molecular mass of air is 28.97 g/mol. Ozone ( O3 ) is not included due to its high variability. composition of dry clean air near sea level according to standard ISO 2533 - 1975 Gas Content of volume \% Nitrogen, N2 78.084 Oxygen, O2 20.9476 Argon, Ar 0.934 Carbon dioxide, CO2 0.0314 * Neon, Ne Helium, He Krypton, Kr Xenon, Xe Hydrogen, H2 Nitrous oxide, N2O Methane, CH4 Ozone, O3 , in summer up to * Ozone , O3, in winter up to * Sulphur dioxide , SO2 up to * Nitrogen dioxide, NO2 up to * Iodine, I2 * * The content of the gas may undergo significant variations from time to time or from place to place  ] ] .
Atmospheric composition upright=1.3|Visualisation of composition by volume of Earth's atmosphere. Water vapour is not included as it is highly variable. Each tiny cube (such as the one representing krypton) has one millionth of the volume of the entire block. Data is from NASA Langley.The composition of common nitrogen oxides in dry air vs. temperature.Chemical composition of atmosphere accordig to altitude. Axis: Altitude (km), Content of volume (\%). Average composition of dry atmosphere (mole fractions) Gas per NASA Dry clean air near sea level(standard ISO 2533 - 1975) Nitrogen, N2 78.084\% 78.084\% Oxygen, O2 20.946\% 20.946\% Minor constituents (mole fractions in ppm) Argon, Ar 9340 9340 Carbon dioxide* a , CO2 400 314 b Neon, Ne 18.18 18.18 Helium, He 5.24 5.24 Methane a , CH4 1.7 2.0 Krypton, Kr 1.14 1.14 Hydrogen, H2 0.55 0.5 Nitrous oxide, N2O 0.5 0.5 Xenon, Xe 0.09 0.087 Nitrogen dioxide, NO2 0.02 up to 0.02 Ozone*, O3 , in summer up to 0.07 Ozone* , O3, in winter up to 0.02 Sulphur dioxide* , SO2 up to 1 Iodine*, I2 0.01 Water Water vapour* Highly variable (about 0–3\%);typically makes up about 1\% Notes The mean molecular mass of dry air is 28.97 g/mol. *The content of the gas may undergo significant variations from time to time or from place to place . a]The concentration of CO2 and CH4 vary by season and location. b]CO2 here is from 1975, but has been increasing by about 2–3 ppm annually (see Carbon dioxide in Earth's atmosphere) .
A
Dry clean air near sea level(standard ISO 2533 - 1975)
A
78.084\%
A
20.946\%
R
Carbon dioxide
9340 Carbon dioxide*
A
a
A
314
A
b
A
18.18
R
Methane
5.24 Methane
A
a
A
2.0
A
1.14
A
0.5
A
0.5
A
0.087
R
Water Water vapour Highly variable;typically makes up about 1\% Notes: the concentration of CO2 and CH4 vary by season and location. The mean molecular mass of air is 28.97 g/mol. Ozone (
up to 0.02 Ozone*,
D
) is not included due to its high variability.
D
composition of dry clean air near sea level according to standard ISO 2533 - 1975 Gas Content of volume \% Nitrogen, N2 78.084 Oxygen, O2 20.9476 Argon, Ar 0.934 Carbon dioxide, CO2 0.0314 * Neon, Ne Helium, He Krypton, Kr Xenon, Xe Hydrogen, H2 Nitrous oxide, N2O Methane, CH4 Ozone, O3
R
* Ozone
0.07 Ozone*
R
* Sulphur dioxide
0.02 Sulphur dioxide*
R
* Nitrogen dioxide, NO2 up to * Iodine,
1 Iodine*,
R
* * The
0.01 Water Water vapour* Highly variable (about 0–3\%);typically makes up about 1\% Notes The mean molecular mass of dry air is 28.97 g/mol. *The
A
.
A
a
A
The concentration of CO2 and CH4 vary by season and location.
A
b
A
CO2 here is from 1975, but has been increasing by about 2–3 ppm annually (see Carbon dioxide in Earth's atmosphere)