The Monte Carlo method was applied to an impact model to investigate the im
pact of polydisperse microparticles with surfaces. The Monte Carlo results
were compared to experiments. Two different situations were examined: the n
ormal (90 degrees) impact of microspheres with a molecularly-smooth silicon
surface, and the oblique (< 90 degrees) impact of microspheres with a Form
ica surface. In the former, the percentage of microspheres captured by the
surface and the overall capture velocity distribution were determined given
the statistical distribution of the microsphere diameters. In the latter,
both the Formica surface roughness angles and the diameters of the microsph
eres were treated as statistical variables. The mean values of the Monte Ca
rlo simulation of the coefficient of restitution and the impulse ratio were
found to agree with the data at the 95% confidence level. Finally, this ap
proach was applied to model the impact of Lycopodium spores with a Formica
surface.