Wind Tunnel Study on Aerodynamic Particle Resuspension from Monolayer and Multilayer Deposits on Linoleum Flooring and Galvanized Sheet Metal

Abstract

Resuspension is an important source of indoor particles and the amount of dust loading is an important factor in resuspension emission rates. Field studies have shown that light to heavy dust loads can be found in the indoor environment, on both the surfaces of flooring and ventilation ducts. These diverse particle deposits can be broadly classified as either a monolayer, in which particles are sparsely deposited on a surface, or a multilayer, in which particles are deposited on top of one another and there is particle-to-particle adhesion and interaction. This experimental wind tunnel study explores the role of the type of particle deposit on aerodynamic resuspension from linoleum flooring and galvanized sheet metal. Resuspension fractions are reported for both monolayer and multilayer deposits exposed to a wide range of air velocities. The type of particle deposit is found to strongly influence resuspension. In general, the results show that resuspension from multilayer deposits can occur at significantly lower velocities compared with monolayer deposits. For example, resuspension fractions at an air velocity of 5 m/s for the canopy layer of multilayer deposits were similar to those found for monolayer deposits at 50 m/s. Additionally, for multilayer deposits, resuspension fractions for the canopy layer increased with increasing dust load and negligible resuspension occurred along the surface layer. It was found that the relationship between the particle deposit height and the viscous sublayer thickness of the airflow can help explain the differences in resuspension that were observed between the two types of deposits. The impact of the type of particle deposit on

Clothing as a transport vector for airborne particles: Chamber study

“…These findings are consistent with previously reported observation of increased fraction of released particles at higher surface loadings on hardwood and vinyl flooring . Other findings indicate that released fraction can either decrease, increase, or remain unchanged at higher surface dust loadings, contingent on the surface material and porosity, relative humidity, particle size and penetration, and deposit type . The scale of dust loadings used in our study is most likely to yield a less‐than monolayer deposit.…”

A comparative study of walking-induced dust resuspension using a consistent test mechanism

“…Boor et al. () conducted a wind tunnel study to investigate the effect of particle deposit structure on aerodynamic particle resuspension on flat surfaces. They found that particles were significantly easier (lower air velocity required) to resuspend from multilayer deposits than monolayer deposits.…”

The atmospheric chemistry of indoor environments

“…129,130 Another common source of indoor particles is via mechanical processes, such as humans walking or air ow, which leads to the generation and/or resuspension of large particles such as dust, carpet bres, etc. 131,132 In the absence of in situ particle production, the major source of indoor particulate matter (PM) is inltration of outdoor aerosol particles through walls and windows. This leads to PM mass loadings being typically lower than those outdoors.…”