Active-flow systems enhance respirator fit success in children: a comparative study with standard disposable models

Information from the abstract

Introduction Children face disproportionate air pollution health risks due to their physiology and behavior. Respirator efficacy data in children remain limited. This study compared standard respirators with a modified active-flow system providing positive pressure. Methods Quantitative fit testing was performed on 82 children aged 5–10 years in Chiang Mai, Thailand, using the TSI Portacount Pro Plus 8,038. Success was defined by an overall mean fit factor of 100 or greater. The evaluation compared a horizontal triple-fold KN95-equivalent respirator with an active-flow model by connecting the mask to a system that provides a continuous supply of purified air from a portable HEPA-filtered unit delivering 66.5 liters per minute. Eight facial dimensions were measured via 2D photogrammetry to identify anthropometric correlations with performance. Fit testing incorporated four standardized exercises, namely bending, talking, side-to-side head turning, and up-and-down head movement, following a modified OSHA quantitative fit-testing protocol. Results Standard filtering facepiece respirators (FFRs) achieved a pass rate of only 3.7%. The active-flow system significantly increased the pass rate to 23.2%, with an odds ratio of 17.0, and increased the overall median fit factor from 9.5 to 39.5. Fit success was positively associated with bizygomatic breadth (aOR 1.31) and menton-sellion length (aOR 1.11), whereas a wider interpupillary distance was associated with lower odds of passing (aOR 0.67). Among the tested exercises, up-and-down head movements resulted in the lowest fit improvements. The participants reported significantly easier breathing under the active-flow condition (86.6%) than under the standard respirator (37.8%), although inconvenience was reported more frequently with the active-flow model (76.8%) than with the standard model (35.4%). Conclusion These findings suggest that FFRs commonly available in consumer markets may offer only limited protection for children against environmental pollutants. Active-flow systems appeared to improve both efficacy and respiratory comfort, though overall protection levels observed in this evaluation remained below thresholds generally considered protective. Given the scope of this evaluation, further research is needed to confirm these findings across broader conditions and populations, with particular attention to improving nasal seal integrity and developing portable, comfortable-to-use units with adjustable flow rates suited to real-world activity levels.

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Related topics: Infection Control and Ventilation · Occupational Health and Performance · Air Quality and Health Impacts