Effects of surgical masks on aerosol dispersion in professional singing

Abstract

Background In the CoVID-19 pandemic, singing came into focus as a high-risk activity for the infection with airborne viruses and was therefore forbidden by many governmental administrations. Objective The aim of this study is to investigate the effectiveness of surgical masks regarding the spatial and temporal dispersion of aerosol and droplets during professional singing. Methods Ten professional singers performed a passage of the Ludwig van Beethoven’s “Ode of Joy” in two experimental setups—each with and without surgical masks. First, they sang with previously inhaled vapor of e-cigarettes. The emitted cloud was recorded by three cameras to measure its dispersion dynamics. Secondly, the naturally expelled larger droplets were illuminated by a laser light sheet and recorded by a high-speed camera. Results The exhaled vapor aerosols were decelerated and deflected by the mask and stayed in the singer’s near-field around and above their heads. In contrast, without mask, the aerosols spread widely reaching distances up to 1.3 m. The larger droplets were reduced by up to 86% with a surgical mask worn. Significance The study shows that surgical masks display an effective tool to reduce the range of aerosol dispersion during singing. In combination with an appropriate aeration strategy for aerosol removal, choir singers could be positioned in a more compact assembly without contaminating neighboring singers all singers.

Impulse dispersion of aerosols during playing the recorder and evaluation of safety measures

“…Similar to previous experiments 14, [19][20][21][22][23] , the video footage was converted into negative black and white. The subjects were asked to wear black clothes.…”

“…They were asked to avoid any motion after finishing the tasks. As in previous experiments 14, [19][20][21][22][23] , the measurements were conducted in a Bavarian Television Broadcasting Studio with the dimensions of 27 m x 22 m x 9 m. Three synchronized high-definition television cameras (Sony, Tokio, Japan, resolution 1920 × 1080 pixels, 25 fps) recorded the tasks from a side view (C1), a front view (C2) and a top view (C3). The studio was aerated before and after each task with opposed doors open for a minimum of 2 minutes.…”

The Effect of Water Resistance Therapy on the Impulse Dispersion of Aerosols During Sustained Phonation

“…8 , 32 , 33 To not trigger convectional flows, the subjects were standing still on the same marked point on the stage during inhalation and exhalation. Similar to previous studies, 9 , 10 , 11 , 12 , 18 , 34 the study was conducted in a Bavarian Television Broadcasting Studio with the dimensions of 27 m x 22 m x 9 m. Three synchronized high-definition Sony television cameras (Sony, Tokyo, Japan, resolution 1920 × 1080 pixels, 25fps) recorded the tasks from a side view (C1), a front view (C2), and a top view (C3). Before and after all tasks and each subject the hall was aerated via opposing doors opened for a minimum of 2 minutes.…”

“…The analysis was performed similarly to previous investigations, 9 , 10 , 11 , 12 , 18 , 35 where the video footage was edited and set into a coordinate system to measure the aerosol cloud's expansion over time. The video editing included converting the footage into negative black and white, and objects that could have led to segmentation errors were masked.…”

“…As a consequence, safety concepts, such as distancing, singers’ masks, room aeration systems, plexiglass walls, etc have been invented and evaluated, in order to assess and reduce the transmission risks as much as possible and to make musical gatherings, ie, lessons, rehearsals, and performances, possible and safe. 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 …”