Biotrickling filtration is a potential and cost effective alternative for the treatment of volatile organic compound (VOC) emissions in air, so it is necessary to deepen into the key aspects of design and operation for the optimization of this technology. One of these factors is the oxygen mass transfer of the process. This study would facilitate the selection of the packing material and the mathematical modelling and simulation of bioreactors. Four plastic packing materials with a different specific surface area have been evaluated in terms of oxygen mass transfer. For the tested range of superficial liquid velocities, data show a relationship between the kLa and the superficial liquid velocity in all packing materials used, except for the biggest plastic rings. No significant differences in mass transfer coefficients at low liquid velocities were observed, however dependency between oxygen transfer and specific surface area increased considerably for high liquid velocities. No significant influences of the superficial air velocity were observed.