Innovative Test Bench for Comprehensive Evaluation of Portable Air Cleaner Performance Against Infectious Human Respiratory Pathogens

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Abstract
Background: The COVID‐19 pandemic has underscored the critical role of indoor air quality and ventilation in the transmission of respiratory viruses. Although portable air cleaners (PACs) have proliferated in recent years, most performance evaluations rely on indirect measurement approaches or surrogate microorganisms, leaving uncertainty regarding their true efficacy against infectious human bioaerosols. Objectives: We aimed to develop and validate a highly controlled test bench for comprehensive evaluation of PACs in accordance with evolving standards, incorporating infectious respiratory human pathogens, spectrometric analysis under realistic environmental conditions, and computational fluid dynamics (CFD) supporting experimental design and interpretation of airflow patterns. Methods: The experimental platform consists of a 20 m 3 BSL‐3 chamber equipped for precise control of airflow, humidity, and temperature, allowing nebulization of infectious viruses (SARS‐CoV‐2, influenza A/H1N1pdm09, and adenovirus), bacteria ( Staphylococcus aureus ), and fungi ( Aspergillus fumigatus ). Natural decay rates and stabilities were characterized for each microorganism in homogeneous, highly contaminated atmospheres. The performance of a HEPA H14 PAC (Camfil City M) was evaluated under varying positions (center/corner) and airflow scenarios, with additional interference simulated by open‐window ventilation. Air samples were analyzed by TCID50 assays and particle spectrometry. Results: Stable contaminated atmospheres were reproducibly generated, with airborne concentrations remaining stable for at least 1 h. S. aureus exhibited the greatest stability, while adenovirus and influenza A decayed more rapidly. PAC efficacy depended on device placement and ventilation conditions, with synergistic effects observed when combining air filtration and ventilation. Experimental decay rates for infectious virus and aerosols consistently exceeded CFD predictions, likely due to modelling limitations. Conclusions: This study presents an advanced methodology for evaluating PAC performance against infectious airborne pathogens under realistic, variable environmental conditions. The findings underscore the importance of considering infectious bioaerosol dynamics, device placement, and airflow characteristics when assessing PAC effectiveness and highlight the limitations of solely modelling inert particles in CFD analyses.
Funding Information
  • Bpifrance (DOS0218327/00)
  • Région Auvergne-Rhône-Alpes (23 005786 01)

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