Occupants and Surface Types Drive Microbial Dynamics in Controlled Indoor Environments

Indoor microbial communities are integral to indoor environmental quality and human health, shaped by occupant activity, surface characteristics, and environmental conditions. While previous studies has examined occupant-driven microbial dispersal or surface-associated microbiomes, few have assessed their interactions systematically under controlled conditions over time. Moreover, microbial persistence and dispersal in Heating, Ventilation, and Air Conditioning (HVAC) systems remain poorly understood, despite their role in airborne microbial transport. To address these knowledge gaps, we conducted a controlled, long-term (1.5-year) investigation evaluating how human presence, and environmental conditions (humidity, ventilation, seasonal variations) drive bacterial and eukaryotic dynamics across airborne and surface-associated (dry vs. wet) microbiomes in a compact urban housing model.