Airborne transmission of disease in stratified and non-stratified flow

Airborne transmissions take place as a transport of virus or bacteria via the aerosol flow in rooms. The distribution of aerosols tends to be evenly distributed if the flow in the room is fully mixed. The aerosols distribution will be different if the room air is stratified. A vertical temperature distribution may create stratified layers with either lower or higher concentrations of exhalation from the infected person. The use of the stratification effect made it possible to create a reduced cross-infection risk for long range airborne transmission in some situations, but we need research in system layout to find solutions which will give a safe environment in all practical situations. A solution must be followed up with some necessary restrictions/information of use, if necessary. Another possibility is to use mixing ventilation and accept a higher flow rate of outdoor air.