Chamber bioaerosol study: outdoor air and human occupants as sources of indoor airborne microbes

• Published in: PloS one Vol. 10; no. 5; p. e0128022
• Main Authors: Adams, Rachel I, Bhangar, Seema, Pasut, Wilmer, Arens, Edward A, Taylor, John W, Lindow, Steven E, Nazaroff, William W, Bruns, Thomas D
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 29-05-2015; Public Library of Science (PLoS)
• Subjects: Aerosols; Air - analysis; Air Microbiology; Air Pollution, Indoor - analysis; Airborne microorganisms; Bacteria; Bacteria - genetics; Bioaerosols; Biology; Carpets; Deoxyribonucleic acid; DNA; DNA sequencing; Environmental engineering; Environmental Monitoring - methods; Experiments; Foreign exchange rates; Fungi; Fungi - genetics; Gene sequencing; Humans; Humidity; HVAC; Indoor air quality; Indoor environments; Microbial colonies; Microbial Consortia - genetics; Microorganisms; Outdoor; Skin; Taxa; Ventilation; United States
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0128022

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.