The atmosphere of the planet Mars is composed mostly of carbon dioxide. The atmospheric pressure on the Martian surface averages 600 pascals, about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals.

Oxygen: 0.13%

Carbon dioxide: 95.32%

Carbon monoxide: 0.08%

Nitrogen: 1.9%

Argon: 1.6%

Chemical species: Mole fraction