A relatively large number of viruses can come out of the clarinet. It emits significantly more aerosols that may contain pathogens such as SARS-CoV-2 compared to other instruments such as a flute. However, the risk of transmission from an infected person playing a wind instrument is generally much lower than for people who sing or speak, provided the person spends the same amount of time around them. This was the conclusion reached by a research team from the Max Planck Institute for Dynamics and Self-Organization (MPI-DS) in Göttingen and the University Medical Center Göttingen (UMG) in a comprehensive study. Researchers have determined particle emissions and the corresponding maximum risk of transmission while playing various wind instruments. The results provide clues as to how cultural events can be organized with the lowest possible risk of infection, even during a pandemic.
The riskiest tool is the voice, at least when it comes to spreading viruses like SARS-CoV-2. Compared to quiet breathing, when singing or talking, infected people release more than 500 times more particles into the air that may contain viruses. When people play wind instruments, significantly less aerosol is released into the environment than when singing, but still 5 to 50 times more than when breathing, a team led by Mohsen Bagheri and Eberhard Bodenschatz, director of the MPI- DS and professor at the Faculty of Physics, University of Göttingen. Together with colleagues from the UMG Institute of Hospital Hygiene and Infectious Diseases, the researchers analyzed how many particles of which size are released when playing 20 different wind instruments. They performed measurements under controlled conditions in a clean room and determined the upper limit of the risk of transmission of the micron variant of SARS-CoV-2 based on the results in each case. The research is publicly available.
The risk of transmission depends on the device
“Surprisingly, we found that musical instruments are less risky than talking or singing,” says Mohsen Bagheri, head of the aerosol research group at MPI-DS. As the research of the group from Göttingen shows, it is mainly the large respiratory droplets that remain trapped in wind instruments, which are particularly important for the transmission of viruses. Thus, the instruments act as filters for larger particles. However, brass music is not harmless to musicians and the public from an infectious point of view. This is due to the fact that mostly particles smaller than five micrometers come out of the device. They stay in the air longer and spread further, so they can reach high concentrations, especially in poorly ventilated rooms. The amount of such small particles released by wind music also depends strongly on the instrument: while the team measured very low concentrations of released particles for various flutes, the measurements gave values almost as high for clarinet as for singing.
For example, at a distance of one and a half meters from the clarinet and trombone, the risk of transmission is up to 50 percent after only four minutes. However, at the same distance from the flute, this risk of transmission is only reached after three hours. All values for other measured instruments were average.
Masks for tools and people protect
In their study, the team also investigated how effectively the transmission risk could be reduced using particle filters with similar properties to the fleece of FFP2 masks. They placed prototype masks on the ends of wind instruments; the woodwind instruments were almost completely covered by the filter material. “For copper instruments, the instrument mask reliably reduces the emission of infectious particles,” said Oliver Shlenczek, lead author of the study. If, in addition, the audience also wears an FFP2 mask, the risk of transmission is no more than 0.2 percent, even after an hour. Simone Scheitauer, director of the UMG Institute of Hospital Hygiene and Infectious Science, considers these results very positive: “On this basis, we can recommend much more targeted protective measures in the future and support musical cultural activities with only minor restrictions even in critical situations,” she says. .
“With proper ventilation and the wearing of FFP2 masks, lessons, rehearsals and concerts with wind instruments can be conducted safely,” concludes aerosol researcher Eberhard Bodenschatz.