Addressing dirty floors is a key, often overlooked, component of infection control. Walking on dirty floors aerosolizes the bacteria and virus back into the air potentially contaminating another surface or it is inhaled. Resuspension of particles – be it bacteria, chemical, viral or particulate matter – impacts health. The copious data that exists suggests strongly that it is a threat that must be recognized.
RESUSPENSION OF ALLERGEN-CONTAINING PARTICLES UNDER MECHANICAL AND AERODYNAMIC FORCES FROM HUMAN WALKING – INTRODUCTION TO AN EXPERIMENTAL CONTROLLED METHODOLOGY. In this study, a reliable and reproducible methodology was developed to explore the influence of human walking on the aerosolization of allergen-containing particles. It finds that: Peak resuspension factor (RF) and resuspension rate (RR) measured in these experiments ranged from 10-6 to 10-3 m-1 and 10-5 to 10-2 min-1, while average RF and RR ranged from 10-8 to 10-4 m-1 and 10-7 to 10-3 min-1, respectively. Despite the four order of magnitude range, these values fall between field measured values found in the literature review. The main observations derived from the experiments performed were: (1) for a continuous disturbance, resuspension was only observed during the first two minutes with an initial burst of particle reentrainment followed by an exponential decrease to undetectable value; (2) air-puff disturbances had a much higher impact on dust resuspension than the vibration disturbances; (3) particles were more easily resuspended from linoleum flooring than from carpet flooring; (4) German roach dust was more easily resuspended by air streams than quartz dust; (5) RF and RR values derived from the present experiments show consistency with previous research values
The methodology presented has been demonstrated and proven to be a valuable tool to gather reliable information on particle resuspension. The controlled environmental and disturbance conditions, the flexibility to generate different types of disturbances (including a future electrostatic disturbance), the broad range and flexibility of air sampling, the flexibility to use different flooring and different dust such as allergen containing dust and surrogate CBW dusts make it a potential useful tool for particle resuspension research and thereby contribute to the development of exposure risk models.
An evaluation of the impact of flooring types on exposures to fine and coarse particles within the residential micro-environment using CONTAM is found at the Journal of Exposure Science & Environmental Epidemiology. It shows that both flooring type and floor loading had significant impact on incremental concentrations of both fine and coarse particulate matter (PM) due to resuspension from walking.
Surrounded by a Cloud of Dust: Particle Resuspension in Indoor Environments is a splendid presentation by Brandon E. Boor, Ph.D. Assistant Professor of Civil Engineering, Purdue University, at a meeting of the National Academies of Science, Engineering and Medicine.