title: Characterizing particle resuspension from mattresses: chamber study.
abstract: People spend approximately one-third of their lives sleeping, where they can be exposed to a myriad of particle-bound biological agents and chemical pollutants that originate within mattresses and bedding, including allergens, fungal spores, bacteria, and particle-phase semi-volatile organic compounds. Full-scale particle resuspension experiments were conducted in an environmental chamber, where volunteers performed a prescribed movement routine on an artificially seeded mattress. Human movements in bed, such as rolling from the prone to supine position, were found to resuspend settled particles, leading to elevations in airborne particle concentrations. Resuspension rates were estimated for the size fractions of 1-2 μm, 2-3 μm, 3-5 μm, 5-10 μm, and 10-20 μm, and were in the range of 10(-3) to 10(1) h(-1). Particle size had the most significant impact on the resuspension rate, whereas dust loading, volunteer body mass, and ventilation rate had a much smaller impact. Resuspension increased with the intensity of a movement, as characterized by surface vibrations, and decreased with repeated movement routines. Inhalation exposure was characterized with the intake fraction metric. Intake fractions increased as the particle size and ventilation rate decreased and ranged from 10(2) to 10(4) inhaled particles per million resuspended, demonstrating that a significant fraction of released particles can be inhaled by sleeping occupants.
  
  
  CONCLUSIONS
  Full-scale chamber experiments with human volunteers demonstrate that body movements in bed can resuspend settled particles from mattresses, leading to elevated airborne particle concentrations in both the breathing zone and bulk air of the chamber. Numerous variables influence resuspension, including particle size and intensity of a specific body movement. The results suggest that human-induced resuspension in the sleep microenvironment may play an important role in contributing to our inhalation exposure to mattress dust pollutants.
authors: Department of Civil, Architectural, and Environmental Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA.
authors: B E
authors: BE
authors: Boor
authors: Danish Building Research Institute, Department of Construction and Health, Aalborg University, Copenhagen, Denmark.
authors: M P
authors: MP
authors: Spilak
authors: Department of Civil, Architectural, and Environmental Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA.
authors: R L
authors: RL
authors: Corsi
authors: Department of Civil, Architectural, and Environmental Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA.
authors: A
authors: A
authors: Novoselac
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D001513:Beds; D001835:Body Weight; D006801:Humans; D019570:Inhalation Exposure; D009068:Movement; D010316:Particle Size; D052638:Particulate Matter; D014691:Ventilation
chemical_list: D052638:Particulate Matter
keywords: Bedroom; House dust mites; Inhalation exposure; Mattress dust; Resuspension; Sleep