Evaluation of survival rates of airborne microorganisms on the filter layers of commercial face masks

Disposable surgical masks affect the decomposition of Zostera muelleri

The coronavirus pandemic has caused a surge in the use of both disposable and re-usable mask pollution globally. It is important to understand the potential impact this influx of novel pollution has on key ecological processes, such as detrital dynamics. We aimed to understand the impact mask pollution has on the decomposition of a common coastal seagrass, Zostera muelleri. Using an outdoor mesocosm system with heater chiller units and a gas mixer, we were able to test the impact of both re-usable single-ply homemade cotton masks and disposable surgical masks on samples of Z. muelleri detritus under different environmental conditions. We found that disposable masks, but not re-usable masks, significantly increased decomposition of Z. muelleri detritus. This may be due to the increased surface area available for detritivorous microorganism colonisation, driving further decomposition. This could have negative ramifications for seagrass communities and adjacent ecosystems.

Comparison of bacterial filtration efficiency vs. particle filtration efficiency to assess the performance of non-medical face masks

As a result of the current COVID-19 pandemic, the use of facemasks has become commonplace. The performance of medical facemasks is assessed using Bacterial Filtration Efficiency (BFE) tests. However, as BFE tests, require specific expertise and equipment and are time-consuming, the performance of non-medical facemasks is assessed with non-biological Particle Filtration Efficiency (PFE) tests which are comparatively easier to implement. It is necessary to better understand the possible correlations between BFE and PFE to be able to compare the performances of the different types of masks (medical vs. non-medical). In this study BFE results obtained in accordance with the standard EN 14683 are compared to the results of PFE from a reference test protocol defined by AFNOR SPEC S76-001 with the aim to determine if BFE could be predicted from PFE. Our results showed a correlation between PFE and BFE. It was also observed that PFE values were higher than BFE and this was attributed to the difference in particle size distribution considered for efficiency calculation. In order to properly compare these test protocols for a better deduction, it would be interesting to compare the filtration efficiency for a similar granulometric range.