This paper provides an estimate of the average number density of dust particles accumulated around Mars. As investigated earlier, submicron-sided grains (a7 μm have relatively stable orbit forming a disk/torus around Mars, and their lifetime is determined by collisions with the satellite since they stay close to its orbits. Despite the short lifetime of submicron-sized particles and the relatively large volume which contains their trajectories, their number density is comparable with that of particles whose size is between 7 and 50 μm. This is due the fact that submicron-sized grains are thought to dominate the number of escaping particles. We conclude that particles with sizes a<0.5 μm and 7 μm≲a≲50 μm will be the most abundant in the Martian dust environment. ¿ American Geophysical Union 1993