Face masks and respirators may well offer the only way to return to an even remotely normal living and working style in the second half of 2020, which means they will play a vital role in any kind of economic recovery. This article’s purpose is to discuss what we know about respiratory protection, and also what can be done to make masks more effective by reducing air leakage. The effectiveness of a mask made from a particular material can vary enormously as a function of how well it seals against the wearer’s face. If we can enhance the effectiveness of the masks currently in use, we can reduce the danger to everybody.

The article’s primary focus is individual self-protection outside the workplace, and in workplaces where respiratory protection is not required. None of this content, however, constitutes formal occupational health and safety (OH&S) or engineering advice, noting that, with the exception of what is available from the Occupational Safety and Health Administration (OSHA), the National Institute for Occupational Safety and Health (NIOSH), and ASTM International, definitive guidance is in short supply from authoritative sources.

 …