Resuspension of dust particles in a chamber and associated environmental factors

Experiments investigating particle resuspension from human activities were conducted in a full-scale experimental chamber. The experiments tested three types of flooring (vinyl tiles, new and old level-loop carpets) and two ventilation configurations (ceiling and side wall supply systems). The floorings were seeded with 0.1-10 mu m test particles. The airborne particle concentration was measured by an array of optical particle counters (OPCs) in the chamber. Resuspension rates were estimated in size ranges of 0.8-1, 1.0-2.0, 2.0-5.0, and 5.0-10 mu m ranging from 10(-5)-10(-2) hr(-1), with higher resuspension rates associated with larger particles. Resuspension via walking activity varied from experiment to experiment. Heavy and fast walking was associated with higher resuspension rates than less active walking, most likely due to a combination of increased pace, increased air swirl velocity, and electrostatic field effects established by the walking. The type of floorings also influenced the particle resuspension. Given the same size and mass distribution of test particles per unit floor area, resuspension rates for the seeded new level-loop carpet were significantly higher than those for the vinyl tile flooring for larger particles (1.0-10 mu m) under the ceiling air supply system.