The Collaborative International Dictionary of English v.0.48:

Dispersal \Dis*per"sal\, n.
   The act or result of dispersing or scattering; dispersion.
   --Darwin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dispersal
    n 1: the act of dispersing or diffusing something; "the
         dispersion of the troops"; "the diffusion of knowledge"
         [syn: dispersion, dispersal, dissemination,
         diffusion]

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "dispersal":
   aloofness, anarchy, attenuation, breakup, broadcast, broadcasting,
   chaos, circumfusion, confusion, crack-up, deactivation,
   demobilization, detachment, diaspora, diffraction, diffusion,
   dilution, disbandment, discontinuity, discreteness, disintegration,
   disjunction, dislocation, dismissal, disorder, disorganization,
   dispensation, dispersion, disruption, dissemination, dissipation,
   dissolution, distribution, divergence, entropy, evaporation,
   exfoliation, expansion, fragmentation, incoherence, inconsistency,
   nonadhesion, noncohesion, parting, peppering, propagation,
   publication, radiation, release, revolution, scaling, scattering,
   scatterment, separateness, separation, shattering, shotgun pattern,
   sowing, spattering, splay, split-up, spread, spreading, sprinkling,
   strewing, unadherence, unadhesiveness, untenacity,
   volatilization