During severe accidents in nuclear power plants, large amounts of toxic and radioactive substances may be released in particulate form. One way to mitigate the consequences is to direct the contaminated carrier gas through water pools, where a large fraction of particles can be removed. The retention of aerosols in liquid filters, or pool scrubbing, is the subject of intensive ongoing research. Current models to predict the particle removal rates in pools are as empirical as uncertain and lack detailed, high- quality experimental data. Such data is required to validate Computational Fluid Dynamics (CFD), which has recently become a mature tool to simulate slow momentum two-phase flows. In the present paper, we investigate the hydrodynamics of bubbles when gas is introduced in a quiescent pool through a single acrylic glass injector. The work focuses on the globule flow regime to gain detailed understanding on the bubble hydrodynamics. The data is meant to benefit the development of CFD-based aerosol retention models. Highspeed shadowgraphy was used to image the phase interface for different injector diameters and flow rates, as well as to analyze the periodicity of the flow. Data was analyzed with image analysis techniques to determine the bubble volume, aspect ratio, and center of mass velocity. In addition, the actual surface tension was measured using the sessile droplet method with an image analysis procedure. The experiments reveal different formation and oscillation patterns, as well as non-linear behaviours in the bubble volume.