AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Resuspension of Particles Deposited from Consumer Nanosprays: The Effect of Surface Type, Resuspending Force, and Sampling Height
RUIKANG HE, Jie Zhang, Gediminas Mainelis, Rutgers, The State University of New Jersey
Abstract Number: 309 Working Group: The Air We Breathe: Indoor Aerosol Sources and Chemistry
Abstract Increasing application of nanotechnology has resulted in a growing number of nano-enabled consumer products. The release, deposition, and resuspension of particles from such products could be an important contributor to indoor particulate matter, with potential for adverse health effects.
This study investigated the disposition of manufactured nanoparticles from three Ag-based, three Zn-based and one Cu-based consumer sprays released indoors. Sedimentation and resuspension of released particles were investigated in a newly-constructed 2.8×1.6×2.4 m3 chamber. The resuspension of deposited particles was investigated as a function of flooring type (e.g., carpet and vinyl), resuspension force (e.g., walking by an adult and motion of a robotic sampler that simulated a child), and sampling height. Particle deposition was measured in terms of floor mass loading. Button Samplers (SKC Inc.) with 25-mm PTFE filters were used to collect sprays and resuspended particle mass at 0.3 m and 1.1 m heights, and in the experimenter’s breathing zone (e.g., 1.5 m for adult and 0.3 m for simulated child). The resuspension rates were calculated for all investigated variables.
Resuspension rates ranged from 10-4 to 10-1 h-1, depending on the product, floor type, and sampling height. Resuspension rates were 30% to 320% higher for particles resuspended from carpet compared to vinyl, 3% to 195% higher when particles were measured at 0.3 m height than at 1.1 m height, and 19% to 243% higher when particles were resuspended by a walking adult compared to a moving robot. High particle concentrations observed at 0.3 m height showed that young children playing on the carpet could be exposed to high levels of particles resuspended by adults walking nearby.
The observed results suggest that factors affecting particle resuspension, e.g., surface roughness, walking pace, and resuspension forces due to walking should be examined closely in future studies.