Chamber Bioaerosol Study: Outdoor Air and Human Occupants as Sources of Indoor Airborne Microbes

PLoS One. 2015 May 29;10(5):e0128022. doi: 10.1371/journal.pone.0128022. eCollection 2015.


Human occupants are an important source of microbes in indoor environments. In this study, we used DNA sequencing of filter samples to assess the fungal and bacterial composition of air in an environmental chamber under different levels of occupancy, activity, and exposed or covered carpeting. In this office-like, mechanically ventilated environment, results showed a strong influence of outdoor-derived particles, with the indoor microbial composition tracking that of outdoor air for the 2-hour sampling periods. The number of occupants and their activity played a significant but smaller role influencing the composition of indoor bioaerosols. Human-associated taxa were observed but were not particularly abundant, except in the case of one fungus that appeared to be transported into the chamber on the clothing of a study participant. Overall, this study revealed a smaller signature of human body-associated taxa than had been expected based on recent studies of indoor microbiomes, suggesting that occupants may not exert a strong influence on bioaerosol microbial composition in a space that, like many offices, is well ventilated with air that is moderately filtered and moderately occupied.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerosols
  • Air / analysis
  • Air Microbiology*
  • Air Pollution, Indoor / analysis*
  • Bacteria / genetics
  • Environmental Monitoring / methods
  • Fungi / genetics
  • Humans
  • Microbial Consortia / genetics*


  • Aerosols

Associated data

  • SRA/SRP049464

Grant support

Funding was provided by the Alfred P. Sloan Foundation ( to TDB, grant # 88391. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.