Aerosol emission and superemission during human speech increase with voice loudness
By Sima Asadi, Anthony S. Wexler, C. Cappa, Santiago Barreda, Nicole M. Bouvier, W. Ristenpart. Scientific Reports, 2019
926 citations recorded by the source corpus.
Mechanistic hypotheses about airborne infectious disease transmission have traditionally emphasized the role of coughing and sneezing, which are dramatic expiratory events that yield both easily visible droplets and large quantities of particles too small to see by eye. Nonetheless, it has long been known that normal speech also yields large quantities of particles that are too small to see by eye, but are large enough to carry a variety of communicable respiratory pathogens. Here we show that the rate of particle emission during normal human speech is positively correlated with the loudness (amplitude) of vocalization, ranging from approximately 1 to 50 particles per second (0.06 to 3 particles per cm3) for low to high amplitudes, regardless of the language spoken (English, Spanish, Mandarin, or Arabic). Furthermore, a small fraction of individuals behaves as “speech superemitters,” consistently releasing an order of magnitude more particles than their peers. Our data demonstrate that the phenomenon of speech superemission cannot be fully explained either by the phonic structures or the amplitude of the speech. These results suggest that other unknown physiological factors, varying dramatically among individuals, could affect the probability of respiratory infectious disease transmission, and also help explain the existence of superspreaders who are disproportionately responsible for outbreaks of airborne infectious disease.
Subfields: Epidemiology, Modeling and Simulation, Pulmonary and Respiratory Medicine
View Paper: https://www.semanticscholar.org/paper/8954feaa230060999c4f698c1582ffadfd79b0b9
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In Epidemiology
Citations in the corpus
- Aerosol filtration efficiency of household materials for homemade face masks: Influence of material properties, particle size, particle electrical charge, face velocity, and leaks (2020, background): “Their concentrations were found to be an order of magnitude higher than those from breathing (Morawska et al. 2009), increasing with speech loudness (Asadi et al. 2019).”
- Presymptomatic Transmission of SARS-CoV-2 — Singapore, January 23–March 16, 2020 (2020, background): “Speech and other vocal activities such as singing have been shown to generate air particles, with the rate of emission corresponding to voice loudness (7).”
- The coronavirus pandemic and aerosols: Does COVID-19 transmit via expiratory particles? (2020, background): “breathing, and recent work by Asadi et al. (2019) established that the louder one speaks, the more aerosol particles are produced.”
- Airborne transmission of respiratory viruses (2021, background): “Aerosol emission rates increase with airflow velocity and speech volume during activities such as singing and shouting (9, 89, 90).”
- High SARS-CoV-2 Attack Rate Following Exposure at a Choir Practice - Skagit County, Washington, March 2020. (2020, background): “The act of singing, itself, might have contributed to transmission through emission of aerosols, which is affected by loudness of vocalization (1).”
- The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission (2020, background): “Considering the short travel time (0.7 s) between exiting the mouth and the APS detector, and the high relative humidity (59”
- Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives (2020, background): “The number of particles generated varied greatly across individuals, raising the possibility of superspreaders who could be the primary spreaders of viruses by talking [31].”