The airborne spread of SARS CoV-2 becomes much more likely in cases where many people are in poorly ventilated areas – even if everyone is wearing a mask and keeping the recommended 1.5 metres distance from one another. An infected individual can emit airborne particles, i.e. the smallest liquid particles, unnoticed via their breath and infect others. 

Effective ventilation can reduce the concentration of airborne particles and help prevent infection, but with temperatures cooling down in autumn and winter, the tendency to open windows drops. So how can students and instructors be motivated to regularly ventilate rooms during the pandemic? The Bauhaus-Universität Weimar has purchased user-friendly devices just for this purpose – CO₂ meters. These devices will be installed in classrooms in September and will facilitate proper ventilation by objectively measuring the indoor air quality of individual rooms.

The meters measure the CO₂ concentration, which is equivalent to the aerosol concentration, and signal by turning yellow and emitting a warning tone when the CO₂ concentration reaches the critical level of 990 ppm (parts per million) and it is time to ventilate. This way, everyone is alerted if the CO₂ limit has been exceeded. If the threshold is exceeded, the area must be ventilated for a specific amount of time. Once the area has been properly ventilated, the meter will return to green and the area can be used again.

The meters will be installed in at least 15 rooms, meaning that all of the important rooms will be outfitted with this new technology in time for the start of classroom teaching at the beginning of November.