Abstract View
Risk Assessment and Mitigation of Aerosol Driven Transmission during Wind Instrument Plays
RUICHEN HE, Aliza Abraham, Linyue Gao, Jiarong Hong, University of Minnesota
Abstract Number: 656
Working Group: Infectious Aerosols in the Age of COVID-19
Abstract
Aerosol driven disease transmission has raised significant concerns regarding the safety of wind instrument plays. In collaboration with 16 musicians from Minnesota Orchestra, we provide a systematic examination of aerosol generation from 10 types of wind instruments and the transport of aerosols under the orchestral hall settings. We find the aerosol concentration exhibits more than two orders of magnitude variability across different instruments and depends on the dynamic level, articulation pattern, the breathing techniques used for different instrument plays, etc. Through a comparison with aerosol generation from normal breathing and speaking, we categorize the instruments into low (tuba), intermediate (e.g., bassoon, flute, French horn, etc.) and high risk (e.g., trumpet, trombone, etc.) levels. Brass instrument flow increases with music amplitude and their aerosol production exhibits an inverse response to note duration, while woodwinds emit more aerosols when note pitch increases. The regions where the flow speed and aerosol concentration are above the measurable background level vary among instruments but extend no farther than 30 cm from the instrument outlet for all instruments. Farther away, the upward-moving thermal plume induced by the temperature difference between the human body and ambient air is the dominant source of flow and aerosol transport. Covering the trumpet bell with one layer of acoustic fabric reduces the emitted aerosols by ~60% with little impact on the sound quality. Computational fluid dynamics simulations show that placing an air cleaner above the instrument outlet can reduce the aerosols by 90% owing to the thermal plume driving aerosols upwards. Filtration efficiency further increases considerably (~10%) when lowering the ambient temperature from 25 °C to 20 °C to enhance the thermal plume effect. Overall, our findings provide useful insights into the risk assessment and the corresponding mitigation strategies for various musical activities.