The High Council of Public Health (HCSP), whose role is advisory, issued a few recommendations on Monday, in order to avoid contamination with Covid-19 in public places.
It is thus necessary "to open the windows at least 5 minutes every hour" in these places which receive the public, in particular the schools, and to measure the renewal of the air with CO2 sensors, he recommends.
"This control of the aeration / ventilation of establishments open to the public must constitute a strong point on which a health protocol can be based", writes the HCSP.
This is all the more true, he underlines, “when certain barrier measures (in particular the mask or the interindividual distance) are not adapted to the activity of the establishment (restaurant, nursery schools, etc.) ".
"Open two windows to promote air circulation"
"In schools and universities in particular, it is proposed to leave doors and windows open between lessons and lessons," writes the HCSP.
According to him, "only the windows should remain open during lessons or lessons", the ideal being "to open two windows, if possible, to promote air circulation".
“In situations where ventilation is currently not possible or insufficient (blocked windows), technical solutions must be put in place (for example, flaps or ventilators in the upper part of the windows, forced ventilation, etc.) », Specifies the instance.
In this case, the HCSP considers that "the reduction in the occupancy rate of the premises can then contribute to obtaining satisfactory air quality".
Fight against droplets
To better assess air renewal, the HCSP recommends measuring "the carbon dioxide concentration at representative points and periods during occupancy", using CO2 sensors.
"A CO2 concentration above a threshold of 800 ppm (part per million, unit of measurement of the rate of pollution in the air) must in all cases result in not occupying the room and acting in terms of ventilation / air renewal and / or reduction in the number of people admitted to the premises, ”he concludes.
Many scientists insist on the importance of ventilation to fight Covid-19.
We know that the disease is transmitted a lot via aerosols, clouds of droplets produced by the breathing, speech or cries of infected people and which therefore contain the SARS-CoV-2 coronavirus.
These clouds can remain in suspension for several hours, hence the importance of good ventilation to disperse them.