The silhouette of a man is shown, first breathing normally and then beginning to cough heavily. He is first shown without anything covering his mouth. He then uses his hand, the crook of his elbow, and various types of masks. »When coughing without covering the mouth, it is especially clear how easily the air we breathe can permeate a room«, explains Prof. Conrad Völker, Department of Building Physics. For this reason, it is essential to cover your mouth when coughing according to the experiment. »The best method is to cover your mouth with the crook of your arm and to keep your hands clean to avoid spreading viruses and other pathogens via body contact or surfaces«, adds Prof. Völker. The use of respiratory masks also shows an improvement in slowing the spread. Besides that, respiratory masks filter aerosols transporting viruses, but there is no 100% effective method to prevent droplet infection.