Atmospheric Composition (by volume !!)


 

The eleven most abundant gases found in the Earth's lower atmosphere by volume. Of the gases listed, nitrogen, oxygen, water vapor, carbon dioxide, methane, nitrous oxide, and ozone are extremely important to the health of the Earth's biosphere.

Table : Average composition of the atmosphere up to an altitude of 25 km.

Gas Name

Chemical Formula

Percent Volume

Nitrogen

N2

78.08%

Oxygen

O2

20.95%

*Water

H2O

0 to 5%

Argon

Ar

0.93%

*Carbon Dioxide

CO2

0.033%

Neon

Ne

0.0018%

Helium

He

0.0005%

*Methane

CH4

0.00017%

Hydrogen

H2

0.00005%

*Nitrous Oxide

N2O

0.00003%

*Ozone

O3

0.000004%

* variable gases