AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Aerosol Emission during Human Speech
SIMA ASADI, Anthony Wexler, Christopher Cappa, Nicole M. Bouvier, Santiago Barreda-Castanon, William D. Ristenpart, University of California Davis
Abstract Number: 110 Working Group: Health Related Aerosols
Abstract The physical pathways governing airborne disease transmission between humans remain poorly understood. The traditional emphasis has been on coughing and sneezing, which are dramatic expiratory events that yield easily visible droplets. Nonetheless, it has long been known that normal speech also yields expiratory aerosol particles, and indeed recent research indicates that, compared to coughing, speech can actually release even larger quantities of such particles that are too small to see with the naked eye, but are large enough to carry a variety of respiratory pathogens (e.g., influenza). This observation raises an important question: What types of speech emit the most aerosol particles? Here we show that the rate of aerosol particle emission during healthy human speech is correlated with the loudness (amplitude) of vocalization, and that it varies significantly with different articulations. Experimental measurements indicate that speaking in a loud voice (just short of yelling) yields on average a factor of 10 more particles than speaking in a quiet voice (just above a whisper). Furthermore, certain ‘phones’ (the basic units of speech) associated with voiced plosives (e.g., [d]) yield more particles than unvoiced fricatives (e.g., [f]) or nasal obstruents (e.g., [m]). We interpret these results in terms of the egressive airflow rate associated with the vocalization, which is known to vary significantly with both overall loudness and consonant type. The results suggest that individual speech patterns, including language spoken, could affect the probability of airborne disease transmission.