Abstract
The determination of how efficiently filtration systems used for the production of breathing air used in hyperbaric environments are operating is significant both from theoretical and practical points of view. The quality of breathing air and the breathing mixes based on air is crucial with regard to divers' safety. Paradoxically, a change in regulations regarding quality requirements for breathing mixes has imposed the necessity to verify both the technical equipment and laboratory procedures used in their production and verification. The following material, which is a continuation of previous publications, presents results of the conducted research along with the evaluation of effectiveness of the filtration systems used by the Polish Navy.