Setup of a method supporting the adoption of a regeneration strategy for FFP2 masks used by rescuers during the Covid-19 emergency

In the context of the Covid-19 pandemic, the chemical, biological, radiological, and nuclear unit of the Fire and Rescue Service command in Milan sought to prevent potential shortages of disposable FFP2 masks by developing a regeneration method. The method involved establishing a system to verify the protective properties of the masks, with the goal of enabling their reuse. The proposed method is based on a decontamination process that uses dry hot air combined with gaseous ozone, applied through a prototype industrial technology. Validation tests for this method involved subjecting disposable FFP2 masks to two primary stressors: usage (simulated using an artificial respirator) and decontamination. The impact of these stressors on the mechanical and physical properties of the masks was assessed using tests derived from or inspired by the European certification standards for disposable FFP2 masks. Successfully passing these tests indicates that the FFP2 masks are suitable for reuse. This study demonstrates that the decontamination process effectively inactivates E. coli and SARS-CoV-2 (the reference biological agents) and eliminates odors. Validation tests further show that a disposable FFP2 mask can undergo up to twenty decontamination cycles without any significant loss of its protective functions. However, when subjected to cycles of simulated use followed by decontamination—conditions that closely mimic real-world usage—the FFP2 masks exhibit noticeable physical deterioration after more than five cycles. This deterioration compromises the sealing and fit on the wearer's face, rendering the masks unsuitable for reuse beyond five cycles.