Ventilation, as a preventive barrier against COVID-19, has been very blurred during much of the pandemic cycle. With the possible exception of the school environment, where the health and educational authorities have placed a lot of emphasis and the message has transcended. In this regard, we are pleased to share this informative pill that has been prepared by M. Il. Mr. Sebastià Crespí Rotger, full member of the RAMIB, President and Scientific Director of Biolinea Internacional.