The effect of particle resuspension during walking activity to PM10 mass and number concentrations in an indoor microenvironment

Mass and number concentration of particulate matter (PM10) was measured during walking experiments inside a laboratory. In total 20 walking experiments were conducted in a period of 3 months. Particle number concentration was measured in the size range of 0.02-1 μm, while, mass concentration was measured in the range 0.1-10 μm. The PM10 mass increased during the activity, by average 84%, whereas, the walking activity had no impact on particle number concentration. Human induced resuspension rates were examined under different dust loadings. The different dust loadings used (25, 15, 5, 1 g/m2) in order to evaluate the impact of surface loading on the indoor PM10 mass concentration and on the resuspension rate. Walking style was the same in all experiments. Moreover, the experiments involved two different walking patterns inside the laboratory (rectangular and line). The impact of different speed was also examined. The average resuspension rate was calculated to be equal to 10−2-10−3 hr−1. No impact on resuspension rate was observed for different walking patterns or walking speed. On the other hand, the measured mass concentration inside the room was increased when using higher dust loading on the floor, although the estimated resuspension rate found independent on the initially deposited surface dust loading.