Face masks are 'less effective' in the rain, what to do when it gets wet

As we go into one of our soggiest seasons in Canada, it's important to know that the weather could play a role in the effectiveness of your mask.

Officials from the World Health Organization (W.H.O) and the Department of Health and Social Care in the U.K. are advising people to replace their masks if they become wet, as moisture could impact their effectiveness.

The updated guidance started in the U.K. as a PSA since they are entering into a very wet time of year. However, it is advice we could all heed here in Canada, as well, as we transition into one of our soggiest seasons.

“When you look at a mask on a microscopic level, you can see the mask has a net-like type of structure that allows it to trap particles - in the centre of the mask, that is where it's doing its job,” says Infectious Disease Doctor Sumon Chakrabarti. “If you all of a sudden make it wet, it can actually destroy or impair that lattice -- so now particles are not being filtered as readily, and then it will decrease the effectiveness of that mask.”


Researchers say the common blue surgical mask is the most susceptible to this, as it is essentially made of paper. That being said, it does not mean that a fancy multi-layer or filtered mask will work any better when wet. Some Health experts say any mask, no matter what the price or technology, will not work if it becomes damp.

“Another important thing to consider is, let’s say, you are outside in the rain and the mask is getting wet, you can ask yourself why you are wearing the mask to begin with? Generally, if you are not around a lot of other people, wearing a mask outside is really not needed. So, I would recommend when you go outside, and you are away from other people, remove the mask and you can keep it from getting wet,” suggests Dr. Chakrabarti.

WHO: DOs of masks

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W.H.O: Dont's of masks

Courtesy: World Health Organization

The outdoor elements, however, aren’t the only things to consider when it comes to the effectiveness of your masks. Health experts say your mask may become ineffective and damp also from breathing, coughing or sneezing. If this happens, the W.H.O recommends changing the mask as soon as possible with a clean dry one.

As our knowledge about COVID-19 continues to expand, best practices are also changing. The pandemic has caused us to constantly evolve and adapt to this new environment. For more information on COVID-19 in Canada, click here.

Watch the video above for our full interview with Dr. Chakrabarti.


Thumbnail Courtesy:: Unsplash/Mika Baumeister