The smell from the cake leaves the room at high velocities because of diffusion.
Kinetic theory:
The kinetic theory applies to gases and describes their random movement and collisions in the whole volume that they are allowed to fill. This movement depends on factors like temperature and pressure.
Coffee and bacon particles will exist in the air in gaseous form. They will be colliding with each other, with all the other air particles and with the room walls to eventually disperse evenly in the whole room. They will be detected when coming into contact with olfactory receptors in the nose. They will reach the nose at the same temperature and there are equal amounts of particles of each.
