RESPIRATORY FIT TESTING: A COMPARATIVE STUDY ON THE AEROFIT® VS. THE PORTACOUNT(TM) PRO PLUS

Abstract

Respirator fit testing is a critical component of respiratory protection programs and is required to ensure that respirators provide adequate protection in accordance with Occupational Safety and Health Administration (OSHA) standards (29 CFR 1910.134). This study focused on quantitative fit-testing methods, which evaluate respirator fit by comparing particle concentrations outside the respirator to those measured inside the facepiece to generate a fit factor. An emerging quantitative fit-testing technology, the AeroFit®, was compared against the reference device, the PortaCount™ Pro+. Firefighters represent an occupational group with frequent and high-risk respirator use, making proper respirator fit essential during active-duty operations. Thirty-eight firefighters from a fire agency in Northern Colorado volunteered to participate in this study. Each participant completed fit testing on both devices, allowing for direct comparison of overall fit factor values, pass/fail outcomes, testing efficiency, and user experience. Results showed substantial differences in fit factor magnitude between the two devices, with the AeroFit® generally producing higher overall fit factor values than the PortaCount™ Pro+. Equivalence between device fit factor measurements was not demonstrated. Despite these differences, pass/fail outcomes showed a high level of agreement between devices, with only one observed discrepancy. In addition, participants perceived the AeroFit® as faster to complete, more efficient, and it was the most frequently preferred device overall. Overall, these findings indicate that while quantitative fit factor values may vary across fit-testing technologies, both devices can provide fit-testing outcomes that align with regulatory requirements. This study contributes to a clearer understanding of how emerging fit-testing technologies compare to an established reference device and highlights the importance of interpreting fit-testing results within a regulatory and practical context.