Resuspension of expiratory aerosols from indoor surfaces: Preliminary adhesive force measurement

Resuspension of deposited pathogen-laden expiratory aerosols from solid surfaces can occur in indoor environments when disturbed by air turbulence or human activities, such as walking or cleaning. The viable pathogens can then be airborne again and thus pose additional risk to susceptible people. However, this infection risk is always underestimated because of the incomplete understanding of infectious particle resuspension. In this preliminary study, the adhesive forces of expiratory droplets on different common indoor surfaces were measured using the centrifugal technique. Droplets generated by a monodispersive droplet generator were evenly loaded to surfaces of different materials. The resuspension rate was calculated according to the initial number of droplets on the samples and the number of droplets at different rotating speeds. The dependence of resuspension rate on the floor materials was observed. This study provides a better understanding of the resuspension mechanisms of expiratory particles from indoor surfaces and the results can supplement risk assessment of airborne infectious diseases.