Atmosphere of Mars Image of Mars with sandstorm visible, taken by the Hubble Space Telescope on 28 October 2005 General information[1] Average surface pressure 610 Pa (0.088 psi) Composition[2][3] Carbon dioxide 95.32% Nitrogen 2.6% Argon 1.9% Oxygen 0.174% Carbon monoxide 0.0747% Water vapor 0.03% (variable)