REMARK: This Q&A was part of the AIVC special COVID-19 newsletter published in February 2021. To subscribe to the newsletter please click here.

Yes it does. On the one hand, it may spread or disperse viruses from rooms with infection sources to other parts of the building, and on the other hand it may dilute the concentration of infected aerosols in a room where infection sources are present when uncontaminated air is transported from adjacent rooms into the room with infection sources. Transport of air in between rooms may occur through dedicated ventilation transfer openings, through leakage paths in partition walls between rooms, or through open doors. Whether or not transport of air from one room to another is an important phenomenon in the transmission of COVID-19 is depending on many factors, such as the position and strength of infection sources in the rooms, the air flow rates from outside and in between rooms, and the occupancy of different rooms in a building.

Ideally one wants to have a contaminated room in negative pressure relative to other parts of the building. Hence the contamination is kept in the contaminated room and can be diluted to an acceptable level by ventilation. For example, ventilation systems for rooms in hospitals for patients with infectious diseases are designed according to these principles. Still, at the time of writing there is insufficient scientific knowledge to define what ventilation rates are needed to prevent infection from the virus that causes COVID-19. Pressure control is achieved by controlling the flow balance between the supplied and exhausted ventilation airflows to and from a room, often using a mechanical ventilation system. The pressure difference depends on the airtightness of the building envelope and the interior walls, and on the ventilation flow balance.


Willem de Gids, VentGuide, Arnold Janssens, Ghent University, Alireza Afshari, Aalborg University, Gaëlle Guyot, Cerema, Univ. Savoie Mont Blanc


  1. AIVC. AIVC Newsletter Special Issue on COVID-19. February 2021.