The French High Council of Public Health (HCSP) updates its recommendations on ventilation in PAB in the context of the Covid-19 pandemic.

The HCSP recommends the implementation of an environmental strategy to control air quality in each public access building. This control of ventilation in the PAB must be a strong point on which a health protocol can be based, all the more so when certain barrier measures, in particular masks or inter-individual distance, are not adapted to the activity of a re-opened PAB (e.g. restaurants, nursery schools, etc.).

The HCSP recommends ventilating closed spaces in public buildings when people are present and opening windows for at least 5 minutes every hour. In schools and universities in particular, it is proposed to leave the doors and windows open between classes and lessons (cross ventilation). Only the windows should be left open during lessons or lectures (ideally two windows should be opened, if possible, to promote air circulation).

In situations where ventilation is currently not possible or insufficient (e.g. blocked windows), technical solutions should be implemented (e.g. flaps or ventilators in the upper part of the windows, air supply ventilation, etc.). Reducing the occupancy rate of the premises can then contribute to achieving satisfactory air quality.

The HCSP indicates that the air change rate can be easily approximated by measuring the carbon dioxide concentration in the air at representative points and periods during occupancy. A CO2 concentration above a threshold of 800 ppm should in all cases lead to the room not being occupied and to action being taken in terms of ventilation/air renewal and/or reducing the number of people admitted to the premises of an ERP.

Finally, the HCSP recommends that measurement campaigns be carried out in the various PAB (e.g. schools and universities, cultural places, sports facilities, etc.) to identify areas at risk (e.g. certain rooms, corridors and toilets).