Human close contact behavior based respiratory diseases transmission in a university office building

Understanding how respiratory infectious diseases spreads is critical for effective pandemic prevention and control. This study investigated the transmission of aerosol-transmissible respiratory pathogens within an office building for postgraduate students and teachers in Beijing, using SARS-CoV-2 as representative model, focusing on real-time occupancy and close-contact behaviors. Surveillance videos and RGB-D cameras were used to collect data, and a multi–route virus transmission model was established to assess the infection risk and evaluate the effectiveness of non–pharmaceutical interventions. Student offices experienced the longest room usage time (13.2 ± 0.4 h) but a lower room occupancy intensity rate (27.1 ± 7 %) during weekdays. Close contact rate in students and teacher offices ranged from 10 to 11 %, while the conference room displayed the highest rates of 93–96 %. Teacher offices had the lowest average interpersonal distance during close contact (0.73 m), followed by teachers' conference (0.85 m). If a single infected individual were set in the building, people in the student office would face the highest hourly infection risk at 0.12 %. The use of surgical masks and increasing indoor ventilation from 0.5 to 6 air changes per hour reduces the total infection risk by 66.4–76.0 % and 45.0–65.0 %, respectively. Maintaining a distance of 1.5 m when in contact can further lower the total infection risk to 52.8–51.9 %. The findings of this study provide valuable insights for understanding the transmission dynamics of a respiratory infectious disease within the building, essential knowledge for effective prevention and control strategies.