Aktualisiert: Aug 3
Is there a risk of sars-cov-2 infection during normal and vigorous breathing, singing, speaking and loud stage speaking to screaming? And what about the wood and brass instruments in the orchestra? The question arises whether the aerosols produced when singing or making music are sufficient to cause such infections. In the case of the woodwind and brass instruments commonly used in symphony orchestras, it is of interest whether the way they are played increases or decreases the type of droplet formation or changes the particle size. In this investigation, the particle concentrations in the breathing and during singing and speaking and the effective range of the wind instruments were measured with the help of aerosol spectrometers. Three different settings were carried out: professional musicians each with their wind instruments, one actress, one actor, one male and one female opera singer and a total of 36 singers of all ages and different singing styles. Results: Aerosol emissions vary significantly from person to person. There is a compact main group and about one tenth of the tested persons (three out of 40), some of whom deviate significantly upwards. Less aerosols are released when playing wind instruments than when speaking. Apparently no or practically no additional aerosols are produced in the instrument which would aggravate the www.thomaseiche.ch |26.06.2020 | Page 2 of 25 pages problem. On the contrary, it seems that the aerosols get stuck in the instrument and that the instrument works like a filter. Unsurprisingly, the emissions are higher when the wind instrument has keys or is blown over the mouthpiece like a flute. The louder and more expressive the speech, the more aerosols are excreted. The extreme value (see Figure 980 nanolitres per hour was a loud and very fast chanting of a singer who had slightly higher values than the others even when singing normally (see Figure 6). Singing loudly or softly makes only a small difference and for many singers the emission was even lower when singing loudly than when singing softly. This can be interpreted to mean that loud singing also requires clean vocal training, so the emission is lower. Trained, well-trained voices were not clearly distinguishable from less trained voices. Both when playing wind instruments, singing and speaking, the aerosols can be detected in all investigated distances, i.e. up to four meters for wind instruments and seven meters for acting and opera. However, due to the size of the rooms and the air conditioning systems, no accumulation of aerosols took place. This shows the importance of continuous or regular ventilation. For a risk assessment of whether the aerosol quantities found are sufficient for an infection with sars-cov-2, the virus concentrations would have to be known. Such concentrations have, for example, been determined by (Christian Drosten, 2020). A viral load of one million per millilitre is equivalent to one virus per nanolitre. This is the magnitude of most of the results presented here. A viral load of one billion would correspond to 1000 viruses per nanoliter.