Recent eruptions, such as Eyjafjallajökull 2010 (Iceland), have strikingly underlined the vulnerability of our highly globalized societies and highlighted significant shortcomings in schemes currently used to forecast the dispersal of volcanic ash. Thus, for the development of appropriate preparedness and mitigation strategies it is important to have a better assessment and understanding of particle sedimentation and aggregation. In this thesis, first a 4-meter high vertical wind tunnel is introduced that is designed to study the aero-dynamical behavior of non-spherical particles. In the next step, existing protocols for the study of size and shape of irregular particles are assessed and new strategies are introduced. In addition, a new general model for estimating the drag coefficient of freely falling non-spherical solid particles is presented. Finally, by applying a state-of-the-art combination of field and numerical strategies the aggregation of volcanic particles is investigated.