Aerosol Dispersion During Different Phonatory Tasks in Amateur Singers

Due to increased aerosol generation during singing, choir rehearsals were widely prohibited in the course of the CoVID-19 pandemic. Most studies on aerosol generation and dispersion focus on professional singers. However, it has not been clarified if these data are also representative for amateur singers.

Nine non-professional singers (four male, five female) were asked to perform five tasks; speaking (T+), singing a text softly (MT-) and loudly (MT+), singing on the vowel [ə] (M+) and singing with a N95 mask (MT+N95). Before performing the tasks, the singers were asked to inhale 0.5 L vapor produced by an e-cigarette consisting of the basic liquid. The spread of the exhaled vapor was recorded in all three dimensions by high-definition cameras and the impulse dispersion was detected as a function of time.

Regarding the median dispersion to the front, all tasks showed comparable distances from 0.69 m to 0.82 m at the end of the tasks. However, the maximum aerosol dispersion showed a larger variety among different subjects or tasks, respectively. Especially in the M+ task a maximum distance of 1.96 m to the front was reached by a single subject. Although singing with a N95 mask resulted in a slightly increased median dispersion to the front, the maximum dispersion was decreased from 1.47 m (MT+) to 1.04 m (MT+N95).

The maximum dispersion distance to the front of 1.96 m at the end of the M+ task and 1.47 m at the end of the MT+ task showed higher values in comparison to professional singers. Differences in phonation, articulation and mouth opening could lead to greater impulse dispersion. Singing in loud phonation with a N95 mask reduced the maximum impulse dispersion to the front to 1.04 m. Taking all results into consideration, a slightly larger safety distance should be necessary for non-professional singers.