Experiments and simulations of human walking-induced particulate matter resuspension in indoor environments

Abstract

A clean indoor environment, which is essential for human health, can be achieved by reducing PM2.5 pollution from indoor ground fugitive dust. This study quantifies different indoor PM2.5 dust loads and the human walking-induced indoor PM2.5 resuspension for different cumulative times, and investigates the indoor PM2.5 pollution caused by indoor floor dust using experiments and simulations. The concentration of human walking-induced indoor PM2.5 resuspension reached a maximum value of approximately 1 min for different dust loads. The quantitative analysis of PM2.5 resuspension using the particle transport model showed that the magnitude of dust loads was unrelated to the resuspension fraction of PM2.5, and the resuspension fraction of PM2.5 was 2.2 × 10−8. When the indoor PM2.5 dust loads were 0.11, 0.18, and 0.30 g/m2, the diffusion rates of the human walking-induced indoor PM2.5 resuspension were 7.62 × 10−11, 1.25 × 10−10, and 2.08 × 10−10 kg/s, respectively. The movement of PM2.5 concentration and deposition was influenced by airflow from the air conditioner and particles collision with the wall. The source strengths (dust loads) were related to the cumulative time of dust. The indoor PM2.5 concentration increased with the increasing number of people walking indoors. Human walking-induced indoor PM2.5 resuspension leads to an increase in indoor particulate matter; therefore, regularly cleaning indoor dust can reduce secondary pollution caused by indoor activities.