A German scientist set up a special video camera that shows the air expelled when a man coughs. He coughs into plain air, into his hand, his elbow, a dust mask and then into a surgical mask. I'm quite surprised that coughing into your elbow works the best!

Abstand halten! – Wie sich Atemluft beim Husten verbreitet. Ein Experiment der Professur Bauphysik. from Bauhaus-Universität Weimar on Vimeo.