Assessment of bacterial filtraiton and air permeability of face masks used by people during the COVID-19 pandemic

The pandemic caused by SARS-CoV-2 remains a serious threat to human health. Non-specific protection measures including face masks are an effective way to reduce risks of the infection spread. Face masks have different protective capacities and their effectiveness depends on an extent to which a material a mask is made of can retain droplets and aerosol particles containing the virus. Bacterial filtration can be used an as indicator showing how effectively a mask protects from contagion and air permeability can be used to estimate how comfortable it is to wear it. Our research aim was to comparatively assess effectiveness and comfort in wearing provided by masks which were most frequently used by people during the pandemic. We examined medical, cotton, and neoprene masks. Bacterial filtration was determined in accordance with the procedure stipulated in the State Standard GOST 12.4.136-84. Air permeability was estimated by determining how thin air was with VTPM-2 device produced by “Metroteks” LLC. All the data were statistically analyzed with StatTech v. 2.4.1 software package. We calculated quantitative indicators (M ± SD, 95 % CI for normal distribution), Fischer’s test (comparison between groups as per quantitative indicators) and Spearman’s rank correlation coefficient (directions and intensity of correlations). We developed our predictive model using linear regression. The research results indicate that the neoprene mask tends to have the highest bacterial filtration; the cotton mask, the highest air permeability. We detected a correlation between bacterial filtration and air permeability. All masks are quite comparable to a medical one as per all their combined examined characteristics and can be used as a barrier for mitigating risks of droplet infections spread. It is advisable to further investigate face masks with concentrating on more characteristics of their effectiveness, comfort in wearing and safety.