Human Occupancy as a Source of Indoor Airborne Bacteria
Name
Hospodsky-2012-Human occupancy as a.pdf
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446 KB
Format
Adobe PDF
Checksum (MD5)
95ea60ead99f902133e8814ef466a8a9
Author(s)
Hospodsky, Denina
Qian, Jing
Nazaroff, William W.
Yamamoto, Naomichi
Bibby, Kyle
Rismani-Yazdi, Hamid
Peccia, Jordan
Date Issued
April 2012
Journal
PLoS ONE
Publisher
Public Library of Science
Citation
Hospodsky, Denina et al. “Human Occupancy as a Source of Indoor Airborne Bacteria.” Ed. Loren E. Wold. PLoS ONE 7.4 (2012): e34867.
Version
Final published version
Abstract
Exposure to specific airborne bacteria indoors is linked to infectious and noninfectious adverse health outcomes. However, the sources and origins of bacteria suspended in indoor air are not well understood. This study presents evidence for elevated concentrations of indoor airborne bacteria due to human occupancy, and investigates the sources of these bacteria. Samples were collected in a university classroom while occupied and when vacant. The total particle mass concentration, bacterial genome concentration, and bacterial phylogenetic populations were characterized in indoor, outdoor, and ventilation duct supply air, as well as in the dust of ventilation system filters and in floor dust. Occupancy increased the total aerosol mass and bacterial genome concentration in indoor air PM[subscript 10] and PM[subscript 2.5] size fractions, with an increase of nearly two orders of magnitude in airborne bacterial genome concentration in PM[subscript 10]. On a per mass basis, floor dust was enriched in bacterial genomes compared to airborne particles. Quantitative comparisons between bacterial populations in indoor air and potential sources suggest that resuspended floor dust is an important contributor to bacterial aerosol populations during occupancy. Experiments that controlled for resuspension from the floor implies that direct human shedding may also significantly impact the concentration of indoor airborne particles. The high content of bacteria specific to the skin, nostrils, and hair of humans found in indoor air and in floor dust indicates that floors are an important reservoir of human-associated bacteria, and that the direct particle shedding of desquamated skin cells and their subsequent resuspension strongly influenced the airborne bacteria population structure in this human-occupied environment. Inhalation exposure to microbes shed by other current or previous human occupants may occur in communal indoor environments.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1371/journal.pone.0034867
