Impact of different headgear on release of bacteria when wearing a clean air suit for surgery: an experimental study

Journal article, 2026

Background: Staff wearing clean air suits made from tight material affects the level of bacteria in the air in operating rooms. This study investigated the influence of different types of headgear on levels of colony-forming units (CFU) in the air. Wearing no headgear was compared with wearing a disposable cap or a disposable hood, and with results from a previous study with a reusable hood made from the same material as the clean air suit.
Methods: Tests with five healthy males wearing a clean air suit and different types of headgear were performed in a dispersal chamber according to Annex E in European standard EN 13795-2:2019.
Results: The mean source strength value (number of bacteria emitted per second from one person) was 7.3 CFU/s without headgear and 7.2 CFU/S with a surgical cap (P = 0.52). The mean source strength value obtained with a disposable surgical hood was 5.3 CFU/s, which was not significantly lower than that obtained without headgear (P = 0.057).
Discussion: The poor performance of the disposable surgical headgear was likely an effect of both permeable material and design. The mean source strength value with a textile hood in the previous study was 1.0 CFU/s, which was significantly lower than the mean source strength value without headgear (P < 0.01). Conclusion: When high microbial cleanliness of the air in the operating room is required, staff should wear a clean air suit fulfilling the criteria in European standard EN 13795-2, and a hood made of the same material as the rest of the suit.