title: Indoor airborne bacterial communities are influenced by ventilation, occupancy, and outdoor air source.
abstract: Architects and engineers are beginning to consider a new dimension of indoor air: the structure and composition of airborne microbial communities. A first step in this emerging field is to understand the forces that shape the diversity of bioaerosols across space and time within the built environment. In an effort to elucidate the relative influences of three likely drivers of indoor bioaerosol diversity - variation in outdoor bioaerosols, ventilation strategy, and occupancy load - we conducted an intensive temporal study of indoor airborne bacterial communities in a high-traffic university building with a hybrid HVAC (mechanically and naturally ventilated) system. Indoor air communities closely tracked outdoor air communities, but human-associated bacterial genera were more than twice as abundant in indoor air compared with outdoor air. Ventilation had a demonstrated effect on indoor airborne bacterial community composition; changes in outdoor air communities were detected inside following a time lag associated with differing ventilation strategies relevant to modern building design. Our results indicate that both occupancy patterns and ventilation strategies are important for understanding airborne microbial community dynamics in the built environment.
authors.affiliation: Biology and the Built Environment Center, Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Meadow
authors.forename: A E
authors.initials: AE
authors.lastname: Altrichter
authors.forename: S W
authors.initials: SW
authors.lastname: Kembel
authors.forename: J
authors.initials: J
authors.lastname: Kline
authors.forename: G
authors.initials: G
authors.lastname: Mhuireach
authors.forename: M
authors.initials: M
authors.lastname: Moriyama
authors.forename: D
authors.initials: D
authors.lastname: Northcutt
authors.forename: T K
authors.initials: TK
authors.lastname: O'Connor
authors.forename: A M
authors.initials: AM
authors.lastname: Womack
authors.forename: G Z
authors.initials: GZ
authors.lastname: Brown
authors.forename: J L
authors.initials: JL
authors.lastname: Green
authors.forename: B J M
authors.initials: BJ
authors.lastname: Bohannan
mesh_terms: D000389:Air Conditioning; D000391:Air Microbiology; D016902:Air Pollution, Indoor / Q000517:prevention & control*; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D009922:Oregon; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics; D013997:Time Factors; D014495:Universities; D014691:Ventilation
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Airborne bacterial community; Bioaerosol; Built environment; Indoor microbial ecology; Natural ventilation