Biological air filtration is a promising technique for air-quality control in closed environments in space and on Earth, and it offers several advantages over existing techniques. However, to apply it in these environments, specific criteria have to be met. A concept for biological air filtration in closed environments was developed and tested by an international team of specialists. Several model systems for closed environments in space and on Earth were used as a source of contaminated air. Conventional and new analytical techniques were used to determine odour composition and removal efficiency of the filter, including an "electronic nose". The results show that the developed biological air filter is suitable for treating contaminated air in closed environments. The developed electronic nose was shown to be a promising method for air-quality monitoring.