On the durability of surgical masks after simulated handling and wear

After the spread of COVID-19, surgical masks became highly recommended to the public. They tend to be handled and used multiple times, which may impact their performance. To evaluate this risk, surgical masks of Type IIR were submitted to four simulated treatments: folding, ageing with artificial saliva or sweat and washing cycles. The air permeability, mechanical integrity, electrostatic potential, and filtration efficiency (FE) of the masks were measured to quantify possible degradation. Overall, air permeability and mechanical integrity were not affected, except after washing, which slightly degraded the filtering layers. Electrostatic potential and FE showed a strong correlation, highlighting the role of electrostatic charges on small particle filtration. A slight decrease in FE for 100 nm particles was found, from 74.4% for the reference masks to 70.6% for the mask treated in saliva for 8 h. A strong effect was observed for washed masks, resulting in FE of 46.9% (+/- 9.5%), comparable to that of a control group with no electrostatic charges. A dry store and reuse strategy could thus be envisaged for the public if safety in terms of viral and bacterial charge is ensured, whereas washing strongly impacts FE and is not recommended.

Automated summary

This study found that different treatments of surgical masks can affect their performance. Folding, aging, and washing did not significantly impact the masks' air permeability and mechanical integrity, except for washing which slightly degraded the filtering layers. There was a strong correlation between electrostatic potential and filtration efficiency, indicating the importance of electrostatic charges in filtering small particles. Washing had a significant negative impact on the filtration efficiency, and it is not recommended. Public can consider a dry store and reuse strategy for surgical masks if safety in terms of viral and bacterial charge is ensured.