Regularly opening windows or an efficient ventilation system can significantly reduce airborne coronaviruses in hospitals and other facilities, according to the experts.
So-called aerosols are one of the main transmission routes of COVID-19. The solid or liquid particles in the air that we exhale provide the viruses with a convenient “means of transport”. These particles remain in the air for a long time and can spread throughout the entire room in a matter of minutes. At the same time, just the heat emitted by the human body is sufficient to keep the virus-containing particles suspended in the air.
Ventilation concepts to reduce the viral load
The “Aerosols Expert Group” carried out an investigation into which ventilation methods can reduce the concentration of coronaviruses in, for example, patient rooms and waiting areas. This group of scientists includes the Deputy Chair of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute (RKI), Prof. Dr. med. Heike von Baum.
In practice, it is not possible to actually measure the viral load in the air in a room. However, one way to track the virus-carrying aerosols is by measuring the air quality by means of the CO2 concentration. Although the amount of carbon dioxide emitted does not provide a specific measure of the number of virus particles, a low CO2 content is nevertheless indicative of a smaller aerosol load.
The expert panel of engineers, scientists and physicians recommends indoor air quality with a CO2 concentration of less than 800 parts per million (> 800 ppm). According to the scientists, this technical guide value is currently the best means of assessing the amount of aerosols in a room.The CO2 level, and therefore the viral load, in the air can be reduced by:
This is how the experts of the Aerosols Working Group evaluate the various ventilation concepts:
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Dittler A et al. (12/2020). Stellungnahme: Aerosole&SARS CoV2 – Entstehung, Infektiosität, Ausbreitung & Minderung luftgetragener, virenhaltiger Teilchen in der Atemluft. (Letzter Zugriff 02.02.2021) Aerosole_SARS_CoV2.pdf" target="_blank">https://www.baden-wuerttemberg.de/fileadmin/redaktion/m-mwk/intern/dateien/Anlagen_PM/20201204_Stellungnahme_Aerosole_SARS_CoV2.pdf
Positionspapier der Gesellschaft für Aerosolforschung zum Verständnis der Rolle von Aerosolpartikeln beim SARS-CoV-2 Infektionsgeschehen vom 07.12.2020. Letzter Zugriff 02.02.2021. https://www.tropos.de/aktuelles/pressemitteilungen/positionspapier-der-gaef-zum-verstaendnis-der-rolle-von-aerosolpartikeln-bei-covid-19