A system (1) is provided for switching over exhaust air of a bioreactor (2) that has a disposable container (3). The system (1) has at least two exhaust air ducts (4, 5) connecting the disposable container (3) to exhaust air filters (6, 7, 18, 18′). A valve (8) is disposed in at least one of the at least two exhaust air ducts (4, 5) and enables the associated exhaust air filter (6, 7, 18, 18′) to be freed.