Collaborative Research: The mechanics of respiratory particle production in the larynx during phonation

Infectious disease transmission, as highlighted by the COVID-19 pandemic, exacts a severe toll on the physical and psychological well-being, economic development, and health of the global community. To better understand how airborne diseases are spread, this project will determine how speaking generates microscopic respiratory particles that can release infectious pathogens into the surrounding air. Although actions like coughing and sneezing produce high numbers of respiratory particles, these events are not as common as speaking. In comparison, speaking produces particles continuously that results in large quantities of particles being expelled from the mouth over time. The rates at which individuals produce respiratory particles when speaking vary widely among people for unknown reasons. This project will answer this conundrum by performing experiments using both human subjects and physical models of phonation, with the goal of discovering how the mechanics of speaking influences how respiratory particles are produced. This approach will unlock new ways to understand aerosol generation in the vocal tract and how it affects airborne transmission of infectious diseases. Large-scale community outreach efforts through a university sponsored innovation fair (ImagineRIT) will transmit project findings to an interested public. The objective of this project is to elucidate the underlying mechanisms of aerosolized particle generation during phonation and their implications for the transmission of airborne pathogens. The multidisciplinary approach will utilize experimental models and human measurements to quantify the relationship between the biomechanical processes of speech and the mechanics of respiratory particle production. The project will explore how variations in the rheological properties of the respiratory tract lining fluid and the biomechanical actions at the physiological sites of particle generation contribute to the observed heterogeneity in aerosol production rates among individuals. This research is critically important due to the potential for asymptomatic speech-driven transmission of viruses, as evidenced during the COVID-19 pandemic. Findings from this work will inform the development of evidence-based strategies for mitigating infection risk and will have broad application to public health policies regarding airborne diseases. The multi-disciplinary approach of the research plan will also provide a unique educational and training environment for two graduate students and three undergraduates that will participate in the work plan. Research findings will also be incorporated into existing classroom curricula at both the undergraduate and graduate level. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.