Coalescence and size reduction!

fluid

Hi all, one question: I made a simulation of a liquid spray with thermal exchange through air by means of DPM. For what i know, the only model I have included in the simulation that can change the particles dimension is coalescence (no breakup, no evaporation, no wall interaction,...). The question is: why can I see from DPM Histograms that particles diameter after an initial increase then reduces? Increase is direct conseguence of coalescence, of course, but what kind of phenomenon gives me size reduction in this simulation conditions? Can collisions break particles???

Thanks a lot, fluid