Characterizing and Comparing Respiratory Aerosol Emission for Pre-adolescent, Adolescent, and Adults during Sustained Phonation
MAHENDER SINGH RAWAT, Mehtap Agirsoy, Tanvir Ahmed, Byron D. Erath, Goodarz Ahmadi, Dinushani Senarathna, Sumona Mondal, Andrea Ferro,
Clarkson University Abstract Number: 429
Working Group: Aerosol Science of Infectious Diseases: What We Have Learned and Still Need to Know about Transmission, Prevention, and the One Health Concept
AbstractRespiratory activities such as coughing, breathing, singing, sneezing, and speaking release aerosols 0.1-100 μm in diameter, with a mean diameter of ~1 μm for vocalization activities. Several research groups have reported particle production rates for respiratory activities as a function of both loudness and frequency. Few studies, however, have included children, which has restricted understanding of exposure risk in environments occupied primarily by children, such as schools. Respiratory aerosols arise due to bronchial fluid film bursting within the pulmonary tract, vibration of the vocal folds during phonation, and articulation of the tongue/lips/teeth. We expect children's respiratory aerosol generation rates to be lower than adults’ due to the smaller size of their laryngeal structure and reduced subglottal pressure created during speech. We recruited 35 healthy, untrained singers (14 females and 21 males) ages 6 -18 years, as well as 16 adults (8 females and 8 males) ages 20 - 60 years. We investigated particle emissions for vocalizations at 262 Hz (middle C, or C4, on a keyboard) for three different 5-second activities (normal sustained /a/, deep breath followed by sustained /a/, and /pa/ repeated at ~1 Hz). All activities were repeated 6 times. Throughout all of the trials, the rate of respiratory particle generation ranged from 0 to 82 particles per second (#/s). Pre-adolescent children produced fewer particles (mean ± SD equal to 1.8 ± 1.6 #/s) than adolescent children (mean ± SD equal to 4.7 ± 3.5 #/s), who produced fewer particles than adults (mean ± SD equal to 36.9 ± 73.0 #/s). Normal /a/ produced the fewest particles while taking a deep breath prior to producing /a/ generated the most particles for all age groups. Three superemitters (statistical outliers) were found in the adult group, two superemitters in the adolescent group, and three in the preadolescent group.
Keywords: respiratory emission; COVID-19; aerosols; transmission; children, superemitters