Acknowledgements
The authors thank Christoph Thelen and the Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) for the mask testing according to EN 149. Additionally, we would like to thank Susann Widmer, Vanessa Thiele, Karla Bosse, Raphael Kollenberg and Philipp Zaghow, for their excellent technical assistance. Special thanks go to all the participants involved in the experiments. We acknowledge support by the Open Access Publication Funds of the Ruhr-Universität Bochum. 