The composition of air

Composition of Air

The air

Gas Percentage of the gas in air

Nitrogen 79%
Oxygen 20%
Carbon dioxide 0.03%
Water vapour 0.5%
Argon 0.9%
Neon&Helium 0.002%



Water vapour varies from day to day and place to place. For example, the air in Singapore is humid, and it contains large amounts of water vapour. Yet, the air above a desert is very dry, with no water vapour, so the percentage of water vapour will be very low.

This is a chart of the composition of air on Earth


And this being the composition of air on Mars