How to clean a respirator face mask

As speculation continues as to whether or not the government will announce mandatory face mask wearing in certain settings, members of the public everywhere are buying themselves one to try and protect against COVID-19. And with global demand for respirator masks at an all time high, many people are re-using them instead of disposing after just one use.

But how do you look after them properly and how do you ensure not to damage them in the process?

How to clean a respirator mask

The CDC have released guidance on extending the life of an N95 respirator and have recommended how best to reuse them for a limited time. It’s important when trying to care for an N95 mask that you weigh up the decontamination method with the risk of damaging or degrading the integrity of the mask.

The method used to clean the mask must efficiently inactive the viral load, without compromising the filtration or fit. In order to re-use an FFP2/N95 mask or FFP3 mask, it must not be damaged or soiled (with bodily fluids, makeup, etc). There are a number of methods which have shown promising results.

Hydrogen peroxide vapour

Researchers at Duke University have found that N95 masks can be successfully decontaminated using “specialist equipment”. Vaporised hydrogen peroxide was able to permeate the mask layers and kill microbes without deteriorating the mask.

However, it’s important to note that not even some hospitals have the means or equipment to carry out this method and it certainly shouldn’t be attempted at home.

Heat & moisture

If you’re looking for ways to extend the life of your respirator face mask at home (rather than in a medical facility) then there are some simpler ways which are showing promising results.

Although research is still ongoing, there is evidence that supports potential viral inactivation of the coronavirus through the use of heat, humidity and time. There are a number of ways that this can be achieved. One study suggests that an N95 mask can be decontaminated by heating it at 70C for 30 minutes. 

UV light 

This method is already being used by some hospitals, and it’s been indicated that UV-C light can effectively inactivate the virus that causes COVID-19. UV light sanitiser machines can be bought online from various retailers, and can not only sanitise masks but also commonly touched items like your keys or phone.

Time

The saying that time is a great healer is certainly true when it comes to viruses. Without a suitable host (ie, a human body), viruses die after a certain amount of time. Unfortunately, we don’t know exactly how long that is when it comes to the latest coronavirus. However, the common belief among experts is that it could survive on surfaces from a few hours or up to several days.

Therefore, it’s sensible to think that given a suitable amount of time, if your N95  or N99 face mask does have coronavirus on it, simply waiting for the virus to become inactive is a sufficient way to make sure it’s clean. You might therefore wish to have more than one mask, which you can alternate between uses.

Can you wash a respirator face mask?

Unfortunately, the masks are not designed to be washed. This includes wetting it in any way, including spraying it with disinfectant, wetting it with alcohol/sanitiser gel or washing it in soapy water.

This is because FFP2 and FFP3 face masks have a paper outer and inner layer which can disintegrate in water, affecting the filtration of the mask. If your N95 mask doesn’t contain any paper layers, then it could potentially be boiled.

How many times can you re-use a face mask?

There’s no exact guidance to how many times you can re-use a respirator mask, since they are usually designed to be one use only. However, given the current crisis, this is accepted as common practice.

Instead of focusing on the number of times or hours that you can use the mask, you should instead focus on the integrity of it. The OSHA (Occupational Safety and Health Administration) directive indicates that a respirator can be reused as long as it "maintains its structural and functional integrity and the filter material is not physically damaged or soiled". So if your mask is looking worse for wear, it’s probably time to discard it and buy a new one.

However, the most important step in caring for and maintaining an N95 mask remains to be how you use it. Always wash your hands or use a sanitiser gel before fitting the mask and once it’s on comfortably, do not touch it (or any of the rest of your face). When removing the mask, be careful not to cross-contaminate it by touching the outside and then the inside, and always store the mask away from anything else. Most importantly, wash your hands after use.