KRooms should be ventilated for about five minutes every twenty minutes with the windows wide open. This emerges from a recommendation by the Federal Environment Agency for schools on correct ventilation, which was presented on Thursday. The education ministers had asked the Federal Environment Agency to do so. The federal states will now distribute the manual to the schools. It contains recommendations from experts in indoor air hygiene on how correct ventilation in schools can reduce the risk of corona infections.
Political correspondent in Berlin, responsible for “Bildungswelten”.
In the eyes of the experts, it is not enough to ventilate with tilted windows or with only one open window; they also advise against open doors to the corridor. This is because aerosols containing viruses, i.e. air particles enriched with virus, could be transported from one room across the hall to other classrooms without being diluted beforehand by outside air.
Intermittent ventilation or cross ventilation?
“Ventilation is the simplest and most effective measure to remove viruses from the air in classrooms,” said the President of the Federal Environment Agency, Dirk Messner. “Of course, ventilation does not offer one hundred percent protection. The other hygiene measures in accordance with the requirements of the federal states are and will remain important and should be observed in everyday school life, ”warned Messner. Cross-ventilation is ideal when windows on opposite sides of rooms can be opened. With both burst ventilation and cross ventilation, the temperature in the room only drops by a few degrees and then rises again in a short time. According to the Federal Environment Agency, classrooms that cannot be ventilated are out of the question for teaching.
The indoor air hygienists see further advantages in ventilation: CO2, moist and chemical substances are also effectively removed from the air. If the concentration in the interior is too high, CO2 can make you tired and lead to poor concentration. Too much moisture promotes mold. Mobile air purifiers could neither dissipate CO2 nor humidity. In addition, they are usually not able to quickly and reliably rid indoor air of viruses, especially in densely populated classrooms. That is why mobile air purification devices are not suitable as a substitute, but rather as a supplement to active ventilation. According to the handout, CO2 traffic lights are a good indicator of air used.