Inter-flat air flow and the spread of aerosol transmitted infectious diseases

The transmission paths of infectious diseases remained a myth up to now.Our hypothesis is that, on windless days, the outflow from a window on the lower floor of a building will re-enter the immediate upper floor, and therefore bring the droplet aerosols upstairs. The objective of this project is to reveal the mechanisms of this airflow by actuallyquantifying the fraction of the lower-floor exhaust air within the intake air of the adjacent upper floor. This paper reports the preliminary finding of this study.This investigation is performed using the combinination of CFD simulation technique andexperimental tracer-gas and flow visualization technique.The confirmation of this transmission route can have a number of implications to both building design (windows flush with facade should be avoided) and infectious disease control.