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cooking masks in an instant pot kills covid-19. seriously
researchers find that 'cooking' your n95 decontaminates the mask without altering its fit or filtration.
aug 7 2020
3 minute read
turns out rice cookers do a lot more than just cook rice. stock/getty
have you got an n95 mask you’d like to reuse? you might want to look no further than your kitchen. researchers at the university of illinois have discovered that “cooking” an n95 respirator for 50 minutes in a rice cooker, oven or instant pot can effectively decontaminate the mask, and not alter its fit or filtration.
“a pandemic such as covid-19 can cause a sudden depletion of the worldwide supply of respirators, forcing healthcare providers to reuse them,” write the authors of the study , published in the journal environmental science and technology letters.
so the illinois university researchers decided to find an easy-to-use mask decontamination method that was also inexpensive. “we bought an electric cooker from walmart,” says thanh h. nguyen, a professor in the department of civil and environmental engineering at the university of illinois at urbana-champaign, and an author of the study. “our motivation was to find something anyone could do.”
“we found that the dry heat generated by an electric cooker — 100 °c, 5 per cent relative humidity for 50 minutes — effectively inactivated tulane virus, rotavirus, adenovirus, and transmissible gastroenteritis virus,” according to the study. “on the basis of these results, dry heat decontamination generated by an electric cooker, like rice cookers, instant pots, and ovens could be an effective and accessible decontamination method for the safe reuse of n95 respirators.”
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n95 respirator masks provide a closed seal over the nose and mouth, filtering out at 95 per cent or more of airborne particles.
nguyen says that dry heat ensures that the integrity of the mask is not compromised and the fit not altered. fit testing of the masks was performed by the office of occupational safety and health at the university of illinois at urbana-champaign.
the process also doesn’t alter the filtration system of the mask. although the efficiency of the mask was originally 99 per cent, after 20 cycles of 50 minute heating treatments, the particle filtration was still over 95 per cent, says nguyen. “dry heat is the least likely to reduce the filtration efficiency when compared with other available decontamination methods (moist heat, ethanol, isopropanol solution, bleach, and ultraviolet),” according to the authors.
the researchers also point out that if the dry heat is applied to the mask for less than 50 minutes, the virus may not be deactivated sufficiently. “we recommend users measure the temperature during decontamination to ensure the respirator temperature can be maintained at 100 °c for 50 minutes,” they write.
nguyen also warns that the mask should be enveloped in a towel or dishcloth to prevent it from touching the side of the pot and melting. if an oven is being used to decontaminate the mask, it should be placed in a paper bag and no part of the mask should come in contact with the heating element to prevent a fire.
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additionally, the researchers’ guidance only applies to n95 masks, which in the case of the study, were manufactured by 3m – not to surgical of cloth masks.
health canada is currently accepting applications from reprocessors, and manufacturers of reprocessing devices, to develop methods of sanitizing and reusing n95 respirators, which are typically worn by healthcare professionals, according to the canadian agency for drugs and technologies in health . researchers are currently exploring reprocessing masks using ultraviolet light germicidal irradiation (uvgi), vaporized hydrogen peroxide, and heat-based decontamination.
health canada recommends that medical masks, including surgical, medical procedure face masks and respirators “must be kept for healthcare workers and others providing direct care to covid-19 patients.”
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