Surgical masks: analysis of their performances and possible solutions for their reusability

As a consequence of the high virus spreading capability, the COVID-19 outbreak has led to an uncontrolled situation. Several mask types can be used to limit virus diffusion; however, the present project focuses on surgical masks only. This type of masks, regulated by the EN14683:2019 normative, is intended to be a disposable device with the aim of blocking droplets exiting the wearer's mouth and nose and, further, protecting the wearer from external splashes. The starting point of this project is to investigate the mask reusability; this is a crucial issue because the environmental impact caused by disposable masks is gaining increasing importance. To begin with, the study has focused on the evaluation of how the masks' performances vary over time and, it has proceeded with tests (long-run tests) aimed at evaluating their parameters, the differential pressure and the bacterial filtration efficiency, in two types of situations: an intense and prolonged use and a limited use. The combination of two masks has also been investigated. To find effective regenerating strategies, domestic practices have been investigated, among those the use of alcohol, hand washing and industrial washing. Some tests have been also performed on a surgical mask with an interchangeable filter, in order to verify the effectiveness of the washing procedure. The study has demonstrated that masks behave differently and this mainly depends on the type of filter medium placed inside the structure. Some of them do not exhibit any variation in the investigated parameters, whereas others show a significant decrease only in terms of filtration efficiency. Nevertheless, the reusability can be possible by taking the full advantage of mask performances or by following a proper regenerating method. The mask with interchangeable filter is the most ecofriendly alternative and it has demonstrated to be compliant with the standard requirements even after 25 cycles of industrial washing.