Experimental analysis of driving forces and impact factors of horizontal inter-unit airborne dispersion in a residential building

Airborne transmission is responsible for the spread of various respiratory infectious diseases. An internal transmission route of inter-unit dispersion between horizontal adjacent units has been verified in our on-site measurement. In the present study, the impact factors of this transmission route were further investigated using the measurement data, and in particular the contributions of the thermal buoyancy force and the wind force were compared. It is found that the wind force is more dominant than the thermal force. The tracer gas distribution indicates that wind effect and the semi-open condition of the corridor play the main roles in the transmission. Outdoor wind promotes the spread of tracer gas from the index unit to the receptor units, and the effect of wind direction is more significant than the wind speed. Airflow in the semi-open corridor promotes the rapid dilution of contaminants and prevents the accumulation, which can reduce the inter-unit dispersion effectively.