Adaptation to make masks with valves safer for preventing COVID-19 was timely
As reported recently by the Washington Post , CTV News , and NBC News , on Aug 7 2020 the Center for Disease Control (CDC) updated its guidance to warn that masks contain exhalation valves did little to prevent someone with COVID-19 from infecting another person. This is something that was identified by Professor Leighton early in the pandemic, and regrettable since there are vast numbers of such masks in circulation (e.g. for home DIY, and in the construction and technical industries) and their use would reduce the rate at which other, e.g. disposable, masks were being used by first responders and healthcare and social care workers.
Professor Leighton therefore consulted with Carl Knox, at his company Sloan Water Technology Ltd., and together they designed a simple fix that anyone with access to a 3D printer could use to make such masks safer for preventing the spread of COVID infections. They posted the designed for free on the NAMRIP website , along with a video explaining the benefits and disadvantages of the various types of home-made, DIY and commercial masks available.