Can you disinfect your face mask with sunlight? No, says UV Expert

A University of Waterloo professor answers your burning question.

As temperatures rise, the temptation for Canadians to soak up the sunshine is strong. That’s a good thing, as there are plenty of physical and mental health benefits to vitamin D, thanks to the sun’s ultraviolet (UV) rays. Just make sure you’re basking in a physically distant manner. (We’re looking at you, overcrowded park visitors…)

Sunlight’s perks have been getting more positive attention recently, specifically in relation to COVID-19. But contrary to popular belief, the virus can still be spread, no matter how sunny it is outside.

A University of Toronto global study burst that bubble, as researchers found that warmer countries were just as susceptible to COVID-19 as colder countries.

A growing pandemic theory is that sunlight can kill the virus on face masks. This seems to stem from UV light’s sanitation properties: UV light technology has been used to disinfect everything from buses to hospitals and may be a promising tool to make personal protective equipment (PPE) reusable for doctors and nurses.

So, should Canadians be disinfecting their COVID-19 prevention supplies with sunlight?

UV light expert Bill Anderson strongly advises against doing so. Leaving face masks, gloves, and face shields out in the sun won’t accomplish much, the University of Waterloo chemical engineering professor told HuffPost Canada, and that has to do with how natural UV light works.

To fully curb the dreaded line, make sure you’re using a broad spectrum sunscreen. Sunscreen’s SPF is a measurement that determines how much UV-B gets blocked out and doesn’t take UV-A into account. Broad spectrum products offer protection against both wavelengths. SPF 15 to 30 is fine for most people, but SPF 50 might be ideal for those with sun-sensitive skin. Physical sunscreens are considered more environmentally friendly than chemical sunscreens, with early research published in the Journal of the American Medical Association suggesting they might be safer to use in the long-run too.

If you do get a face mask tan line, look on the bright side: These sun marks may be seen in a different light once summer hits its stride.

By the end of this summer, only trust people who have a face mask tan line.
— clever_rogue (@realpaulrichard) May 22, 2020

Al Donato
05/26/2020 06:17pm EDT