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Published on: April 9, 2021
Peak risk of SARS-CoV-2 infection within 5 s of face-to-face encounters: an observational/retrospective study
Takeshi Asai1,2, Erina Kurosaki3, Kaoru Kimachi3
1Faculty of Health and Sports Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, 305-8574, Japan. asai.takeshi.gf@u.tsukuba.ac.jp.
Abstract:
The link between aerosol dynamics and viral exposure risk is not fully understood, particularly during movement and face-to-face interactions. To investigate this, we employed Particle Trace Velocimetry with a laser sheet and a high-speed camera to measure microparticles from a human mannequin's mouth. The average peak time in the non-ventilated condition (expiratory volume, 30 L; passing speed, 5 km/h) was 1.33 s (standard deviation = 0.32 s), while that in the ventilated condition was 1.38 s (standard deviation = 0.35 s). Our results showed that the peak of viral exposure risk was within 5 s during face-to-face encounters under both ventilated and non-ventilated conditions. Moreover, the risk of viral exposure greatly decreased in ventilated conditions compared to non-ventilated conditions. Based on these findings, considering a risk mitigation strategy for the duration of 5 s during face-to-face encounters is expected to significantly reduce the risk of virus exposure in airborne transmission.
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