Is opening windows enough to fight the virus? Does the virus spread more easily with ventilation?

This year ventilation has been a topic of conversation in households across North America. ALDES is here to provide clarity and answer your questions!  A specialist in indoor air quality, ALDES sheds light on what you need to know about the importance of ventilation in light of COVID-19.

Opening windows is sufficient in removing the SARS-CoV-2 virus.

FALSE. Opening windows is easy to do, but it is not enough because it helps to dilute the concentration of the virus only while the window is open. Opening windows can also have negative thermal and acoustic impacts as well as poor air quality when the outside environment is polluted. It must be supplemented by a mechanical ventilation system (CMEV) to ensure a continuous and controlled renewal of air, so as to avoid an accumulation of CO2. A high concentration of CO2 reflects poor ventilation and may therefore contribute to the spread of the SARS-CoV-2 virus. (1)

Mechanical ventilation reduces the risk of transmission.

TRUE. Mechanical ventilation reduces the risk of transmission of the virus by a factor of 10. (2) It is safe to say that a well-ventilated room lowers the risk of transmission and is better for your health.

The SARS-CoV-2 virus can live several days suspended in the air.

FALSE. The virus is spread either by droplets or by airborne microparticles. It can stay several hours in suspension. Maintaining ventilation is therefore essential for renewing the air and preventing the virus from remaining airborne. (3)

Once captured by the filter, the virus dies.

TRUE. The filter will not let the virus escape and go through the ventilation system – Once captured by the filter, the virus dries and dies by itself. (4)

The use of stand-alone air purifiers in a room is enough to free the air from the virus.

FALSE. An air purifier does not renew the air. It is a good complement to mechanical ventilation, which constantly renews the air, treats other indoor air pollutants and thus meets regulatory ventilation standards.

Older buildings do not have ventilation solutions to renew air.

FALSE. There are different mechanical ventilation solutions available and suitable for refurbishment, which guarantee a continuous renewal of the air in each room of the home. An older building does not mean that the ventilation system is inadequate. (5)

1) Agence régionale de Santé PACA (ARS) : COVID-19 – Synthèse des recommandations de gestion de la ventilation /air intérieur
(2) The Lancet Respiratory Medicine, 2020
(3) Haut Conseil de la Santé Publique (HCSP) – Avis relatifs à la réduction du risque de transmission du SARS-CoV-2 par la ventilation et à la gestion des effluents des patients COVID-19
(4) CAMFIL : Virus et Filtration
(5) &