Impulse dispersion of aerosols during playing wind instruments

Abstract

Musical activities especially singing and playing wind instruments have been singled out as potentially high-risk activities for transmission of SARS CoV-2, because of a higher rate of aerosol production and emission. Playing wind instruments can produce condensation water, droplets of saliva, and aerosol particles, which hover and convectional spread in the environmental air and can be potentially infectious.The aim of this study is to investigate the primary impulse dispersion of aerosols during playing different wind instruments in comparison to breathing and speaking. Nine professional musicians (3 trumpeters, 3 cross flutists and 3 clarinetists) of the Bavarian Symphony Orchestra performed the main theme of Ludwig van Beethoven‘s 9th symphony, 4th movement in different pitches and loudness. Thereby, the inhaled air volume was marked with small aerosol particles produced with a commercial e-cigarette. The expelled aerosol cloud was recorded by cameras from different perspectives. Afterwards, the dimensions and dynamics of the aerosol cloud was measured by segmenting the video footage at every time point.Overall, the cross flutes produced the largest dispersion at the end of task of up to maximum distances of 1.88 m in front direction. Thereby it was observed an expulsion of aerosol in different directions: upwards and downwards at the mouthpiece, at the end of the instrument and along the cross flute at the key plane. In comparison, the maximum impulse dispersion generated by the trumpets and clarinets were lower in frontal and lateral direction (1.2 m and 1.0 m in front-direction). The expulsion to the sides was also lower. Consequently, a distance of 3 m to the front and to the sides of 2 m for the cross flutes in an orchestral formation is proposed, for trumpets and clarinets a safety distance of 2 m to the front and 1.5 m between instrumentalists are recommendable.

Aerosol emission rates from playing wind instruments – Implications for COVID-19 transmission during music performance

“…Risk assessment of typical woodwind playing situations Short-range exposure is difficult to model, but easy to mitigate (by social distancing following recommendations, e.g., in Gantner et al and Hedworth et al 18,38 ). The opposite applies for long-range exposure, in practice.…”

“…The plume generated by playing the clarinet has been found to be highly directional, to have high velocity, and to disperse quickly 21 . No air motion could be measured in 2 m distance in front of woodwinds which was the largest reach of aerosol clouds observed 17,18 . A reduction of aerosol emission by 50% (for particles in the size range 0.5 -14 µm) to 79% (0.3 -5 µm) when using a mask around the bell has been found He et al have assessed aerosol emission using aerodynamic particle sizers (APS) directly under the outlet of wind instruments to characterize the aerosol generation of different woodwind and brass instruments 23 .…”

“…Previous studies of aerosol emission during woodwind playing gained important insight on the structure and extension of the nearfield cloud and helped to specify distancing rules for avoidance of short-range exposure. The flow structures in the vicinity of woodwind players have been investigated to characterize the shape, extensions and particle size composition of the primary exhalation cloud [17][18][19][20] . The local air concentration of aerosol has been found to decay to background level on a sub-meter length scale which indicates efficient aerosol dilution in the ambient air 19 .…”

Sources of Aerosol Dispersion During Singing and Potential Safety Procedures for Singers

“…As performed in previous investigations, 11,14 to visualize the expelled aerosols, the subject inhaled the basic liquid of a Lynden Vox e-cigarette (Lynden GmbH, Berlin, Germany), which consists of 50% glycerin and 50% propylene glycol, before performing each task. The e-cigarettes were connected to a spirometer (ZAN100, Oberthulba, Germany) to monitor the inhaled volume.…”

From classic to rap: Airborne transmission of different singing styles, with respect to risk assessment of a SARS-CoV-2 infection

“…The study by the Ludwig-Maximilians-Universität München and the University of Erlangen [6, 7] investigated different forms of speaking and singing with 10 professional singers of the Bavarian Radio Choir. They made respiratory flows visible by exhaling the smoke of e-cigarettes (not containing nicotine).…”