Yes, you can wash your surgical mask and reuse it afterwards; and even up to ten times, without losing its properties. This is the conclusion of a study by French researchers published this fall2021 in the review Chemosphere. Polypropylene Type IIR Surgical Mask “Can be washed up to ten times (…) without any degradation of their filtration or their breathability properties”, underlines this study, the fruit of the work of a consortium set up in the spring of 2020 to study the conditions for reuse of masks, in the midst of the epidemic boom.
“We have chosen a more demanding washing protocol than that of the Medicines and Health Products Agency”, specifies Philippe Cinquin, professor of public health at the University of Grenoble Alpes and at the CHU of Grenoble, very invested in this collective work. That is, washing with detergent in a machine at 60 ° C for 30 minutes. Since the mask retains its properties at this temperature, it is obviously the same at 40 ° C, which the Agency recommends for individuals (1).
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After several washes, specifies the study, the masks lose part of their capacity to protect against liquid splashes – and not aerosols – which has consequences above all in the hospital environment (splashes of blood in the operating room, for example. ).
Pollution after use
At the start of the epidemic, the pressing question was that of the risk of shortages, and therefore of supply. “We depend, even today, on the importation of masks, especially from China. Washing makes it possible to limit this dependence ”, observes Gérard Leseul, Socialist deputy for Seine-Maritime, in charge, in December 2020, of a flash mission to the National Assembly on the “Treatment of used masks”.
This is also the other key issue: pollution after use. “Again, these results are good news, continues the chosen one, because washing your mask several times allows you to generate less waste. In 2020, this pollution was estimated at around 40,000 tonnes ”, emphasizes Gérard Leseul, based on the assessment of the Directorate General for Risk Prevention. While recalling that in France, there is not yet a sufficiently structured and efficient mask recycling channel.
1.5 billion masks already in the oceans …
In the meantime, the plastic contained in our masks is dispersed in the environment, rivers, soils, the sea. “The UN estimates that (…) 1.5 billion masks have already ended up in the oceans”, noted in January 2021 the flash mission of the Assembly. “The ideal is therefore to consume less”, without undermining the imperatives of public health, concludes the deputy.
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So why not stick to the approved fabric mask, which is also washable? For reasons of efficiency, answer the researchers. In their study, they demonstrate that washed surgical masks retain a better performance than those made of cloth. “Faced with the viral risk, they remain recommended for the general population, especially in very frequented places such as the metro, supermarkets, etc. “, thus indicates Philippe Cinquin, at the CHU of Grenoble.
However, after several washes, certain signs should alert – a damaged appearance of the mask, which lint, a bar that fits less well on the nose, etc. It is then the moment to throw it in a well closed trash can – and especially not in the yellow bin.