Comparing aerosol concentrations and particle size distributions generated by singing, speaking and breathing

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has resulted in an unprecedented shutdown in social and economic activity, with the cultural sector particularly severely affected. Restrictions on musical performances have arisen from a perception that there is a significantly higher risk of aerosol production from singing than speaking, based upon high-profile examples of clusters of COVID-19 following choral rehearsals. However, comparing aerosol generation from different types of vocalization, including singing, across a range of volumes is a rapidly evolving area of research. Here, we measured aerosols from singing, speaking and breathing from a large cohort of 25 professional singers in a range of musical genres in a zero-background environment, allowing unequivocal attribution of aerosol production to specific vocalizations. We do not assess the relative volumes at which people speak and sing. However, both showed steep increases in mass concentration with increase in loudness (spanning a factor of 20–30 across the dynamic range measured, p < 0.001). At the quietest volume (50 to 60 dBA), neither singing (p = 0.19) nor speaking (p = 0.20) were significantly different to breathing. At the loudest volume (90 to 100 dBA), a statistically significant difference (p < 0.001) was observed between singing and speaking, but with singing only generating a factor of between 1.5 and 3.4 more aerosol mass. Guidelines for musical performances should be based on the loudness and duration of the vocalization, the number of participants and the environment in which the activity occurs, rather than the type of vocalization. Mitigations such as the use of amplification and increased attention to ventilation should be employed where practicable.

Copyright © 2021 American Association for Aerosol Research

EDITOR:

• Tiina Reponen

Acknowledgments

We acknowledge the Working Group for The Investigation of ParticulatE Respiratory Matter to InForm Guidance for the Safe Distancing of PerfOrmeRs in a COVID-19 PandeMic (PERFORM). BRB acknowledges support from the Natural Environment Research Council through grant NE/P018459/1. Dyson, Inc., the Atmospheric Measurement and Observation Facility, and the Health and Safety Executive are acknowledged for APS loans. Fortius Clinic and Shoen Clinic are acknowledged for the provision of the operating theatre space to conduct the measurements. We acknowledge the BBC Singers, Eleven Management and the performers for volunteering to be included in this study. We acknowledge Public Health England and the Department for Digital, Culture, Media and Sport who acted as sponsor and funded the research, respectively.

Author contributions

FKAG, NAW and CMO are joint first authors on this article. NAW, CMO, PLS, DC and JPR led in the study design and in securing funding. FKAG, BRB, and JPR collected the data. CMO, NAW and PLS prepared the application and secured ethical approval. NAW, CMO, DC and JC managed the registration and coordination of participant volunteers and secured access to the operating theaters. FKAG, LPM, AEH and BRB wrote analysis software and analyzed the data. TF, NG and GCD undertook the statistical analysis. JPR, DC, PLS and JC provided technical guidance and advice. JPR, BRB, NAW, CMO, DC, FKAG and LPM drafted the manuscript. All authors read and approved the final manuscript.

Disclosure statement

The authors declare no competing interests.

Data availability

Correspondence and requests for materials should be addressed to JPR.