Plants have been used decoratively indoors for centuries. For the last 25-30 years, their beneficial abilities to reduce the levels of harmful volatile organic compounds (VOCs) from the indoor air have also been investigated. Previous studies have shown that VOCs are removed by the plant itself, but also by microorganisms in the soil. Furthermore, the rate of removal is dependent on the plant species and can be influenced by exogenous factors such as light intensity and VOC concentration. The research within this field is, however, limited by the fact that the knowledge gained from laboratory experiments is not directly transferrable to real life settings. The largest problem is the use of closed chambers where there is no air exchange. This also results in a declining VOC concentration over time. Due to this limitation, we constructed a new experimental system which among others can allow for air exchange and a constant VOC concentration. With the new system it was found that removal rates obtained in chambers with air exchange and constant VOC concentration were significantly higher than removal rates obtained in closed chambers. This means that removal rates obtained in closed chambers may be an underestimation of the plants' real potential. The next step will be to use the new system to investigate the effects of the exogenous factors temperature, light intensity and CO₂ concentration on VOC removal rates.