Experimental and numerical investigation on aerosol emission in musical practice and efficiency of reduction means
Résumé
Early in the Covid-19 pandemic, musical practices, especially singing and playing wind instruments, have been pointed out as having a high risk of SARS-CoV-2 virus transmission due to a high aerosol production. However, characterization of these emission sources was not consolidated. This study focuses on the generation of aerosols potentially carrying SARS-CoV-2 viruses and protective measures in the context of playing wind instruments and singing. Aerosol concentration reduction means are evaluated using aerosol measurements in clean room and Computational Fluid Dynamics. Measurements at the bell of a clarinet and in front of singers are performed with or without a protection (bell cover for clarinet and surgical mask for singers). Numerical results on clarinet suggest that most of the supermicron (1 μm) particles are trapped on the walls of the instruments, which act as a filter, depending on fingerings which lead to different lateral toneholes positions (closed or opened) changing the frequency of sound. Experimental results are consistent since almost only submicron particles contribute to the measured number concentration during playing clarinet. First of all, the high inter and intra-individuals variability is highlighted, with high coefficients of variation. This study highlights the impact of fingerings and on the generated particles and the efficiency of protections such as bell cover (from 3 to 100 times), depending on the played note and players. Results for singers show that surgical masks significantly reduce the aerosol concentration (from 8 to 170 times), which is also correlated with sound level.