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Avoid unhealthy, toxic breathing with the CO₂ traffic light

17 December 2020 | Focus topics

Avoid unhealthy, toxic breathing with the CO₂ traffic light

Good air means a good learning atmosphere for students and teachers

We produce carbon dioxide (CO₂) when we breathe, which makes it a particularly important factor in classrooms, where many people are present in a limited space.

As early as the 19th century, the hygienist Prof. Max von Pettenkofer investigated the effects of increasing CO₂ levels in assembly rooms. These investigations resulted in the eponymous Pettenkofer number, which sets a maximum acceptable value of 1,000 ppm for indoor spaces. Outdoor concentrations vary between approximately 400 ppm (parts per million) in clean air areas and 500 ppm in urban areas.
Various studies, conducted specifically in classrooms, have shown that after the first lesson of the morning (with year 5 pupils), CO₂ concentrations reached 1,900 to 3,300 ppm.

The seasons also play a part, with CO₂ limits exceeded more quickly in winter than in summer.

The effects of excessive CO₂ concentrations on everyday school life are reduced concentration and performance, increased fatigue and errors and general discomfort, both for teaching staff and pupils.
Recent studies have shown that CO₂ concentration is a very good indicator for the presence of aerosols in the room. This means that increasing the air exchange rate can reduce the aerosol concentration and therefore the risk of infection.

In order to create a learner-friendly and healthy climate in the classrooms for everyone, effective ventilation is essential. This is why the CO₂ warning light with high-quality NDIR 2-beam sensor has been developed. It monitors the current CO₂ concentration in the classroom and clearly signals with coloured lights when ventilation may be needed.

The following signals are integrated:


By providing consistent reminders to regularly air closed rooms, the CO₂ warning light from SAUTER allows effective ventilation when the CO₂ level is too high to reduce the CO₂ and aerosol concentrations in the classroom air. The pupils learn how to ventilate effectively. In addition the symbols teach the pupils that when airing the room (by opening the windows) the radiators should be turned off to save energy. This also raises their awareness of energy conservation.

If you are interested in the SAUTER CO₂ traffic light, please contact the SAUTER office in your region.

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