Mechanical Ventilation, Portable Air Cleaners, and Aerosol Spread

Portable air cleaners may sometimes have unintended effects on aerosol migration in indoor spaces with built-in mechanical ventilation, according to research published earlier this year in Aerosol Science and Technology. Researchers from University College London used particle counters and an aerosol generator to examine how combinations of mechanical ventilation, portable air cleaners, and physical barriers such as doors affected aerosol spread in a hospital outpatient clinic.
Publications from CDC and the National Institute of Environmental Health Sciences from early in the COVID-19 pandemic suggest that portable air cleaners can be effective in reducing aerosol exposures in buildings as supplements to HVAC system ventilation and filtration. The authors of the new study agree that the devices “reduce the aerosol concentration of the space they are placed in for most cases” but highlight the importance of careful planning when using and deploying portable air cleaners. Information from the new study appears below.