Respiratory protection devices (procedural masks, N95 filtering facepiece) were at the heart of prevention measures during the COVID-19 pandemic, as they were considered the best for retaining droplets and aerosols. On the other hand, the face shield played a limited role. Due to limited amount of information on its efficacy, it was not recommended prevention organizations as an alternative to the mask. Despite the high efficiency of filtering layers, some studies have proven that they can be a source of discomfort (heat, sweat etc.) and contribute to plastic pollution. For all these reasons, a reusable protection alternative would therefore be beneficial for both users and the environment. The aim of the present study is to assess the effectiveness of an innovative, custom-ventilated protective face shield designed to reduce pathogen transmission.
Anatomically realistic dummy heads and a test bench were designed to simulate aerosol emission conditions and value the effectiveness of the tested devices in a controlled environment. The test bench equipped with a low-flow, uniformly distributed aeraulic vein consists of a dummy head connected to an aerosol generator (NaCl particles with a median diameter of 0.3 microns and an expiration velocity of around 6 m/s). The aerosol emitted is selected and counted by a Scanning Mobility Particle Sizer (SMPS). The source control efficiency measurement campaign and the statistical analysis allowed us to calculate and compare the effectiveness of the tested devices (N95, surgical mask and visor prototype) in four configurations, with a view to simulating different airborne virus transmission scenarios.
The results obtained show that the effectiveness of the visor prototype varies between 1 % and 11.3 %, across all configurations. The N95 offers better effectiveness (between 82.34 % and 98.47 %), followed by the surgical mask with an effective percentage that varies between 53.7 % and 80.2 %. The recommendations made will improve the face shield prototype and contribute to the development of varied protection strategies, better suited to the specific needs of certain users in the prevention of future pandemics.
| Date | 11 Mar 2026 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Lucas Hof (Supervisor) & Stéphane Hallé (Co-supervisor) |
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Bessom Bekoute, L. (Author),
Hof (Supervisor) &
Hallé (Co-supervisor),
11 Mar 2026Student thesis: Master's thesis › Master in Engineering: Engineering