Particulate matter is a statistical ensemble of interacting, non-identical particles. The fluidization and dispersal of dust is considered here fi om kinetic arguments and experiment. It is concluded that fluidization and dispersal of dust are independent physical processes arising from the action of vibration and steady stresses, respectively. Although the transition or correlation function for particulate systems is not as sharply defined as for the ideal-gas case, its general character is analogous with that for a condensing phase-transition with its critical condition broadened by the distribution of binding energies between the particles. The ratio of the net steady stress on the particles to the vibrational energy is the controlling factor in particle capture and entrainment.