Risk assessment and mitigation of airborne disease transmission in orchestral wind instrument performance. (September 2021)

• Record Type: Journal Article
• Authors: Abraham, Aliza; He, Ruichen; Shao, Siyao; Kumar, S. Santosh; Wang, Changchang; Guo, Buyu; Trifonov, Maximilian; Placucci, Rafael Grazzini; Willis, Mele; Hong, Jiarong
• Is Part Of: Journal of aerosol science. Volume 157(2021)
• Publication Date: 2021-09
• Subjects: Airborne disease transmission -- Aerosol concentration -- Influence zone -- Musical instrument -- Risk mitigation -- Human thermal plume; Aerosols -- Periodicals; Aerosols -- Periodicals; Aérosols -- Périodiques; 541.34515
• DOI: 10.1016/j.jaerosci.2021.105797
• Languages: English
• ISSNs: 0021-8502

Abstract

Abstract: In collaboration with 16 musicians from the Minnesota Orchestra, we assess the airflow and particle concentration emitted from ten wind instruments under realistic performance conditions. Anemometer and schlieren measurement techniques are used to quantify the air flow, and aerodynamic particle sizer, laser sheet, and digital inline holography techniques are used to measure the particle concentration. The regions where the flow speed and particle concentrations are above the measurable background level vary among instruments depending on both air flow generation and particle production, but extend no farther than 30 cm from the instrument outlet for all instruments. Farther away, the upward-moving thermal plume generated by the temperature difference between the human body and ambient air is the dominant source of flow and aerosol transport. Brass instrument air flow increases with music amplitude and particle concentration exhibits an inverse response to note duration. Woodwinds emit more particles when note pitch increases. Covering the trumpet bell with one layer of acoustic fabric reduces the emitted particle concentration by ~60% with little impact on the sound quality. Adding more mask layers blocks more particles, but impedes performance and lowers the sound quality at higher frequencies (>1000 Hz). Computational fluid dynamics simulations initialized with experimental data show that placing an air cleaner above the instrument outlet can reduce the particle concentration by 90% due 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 temperature difference with the human body. Highlights: We studied airflow and particle emission from wind instruments in an orchestra hall. Particle concentration hits background level within 30 cm of each instrument outlet. Human thermal plume suppresses lateral spread of particles at the breathing level. Air purifier placement and ambient temperature largely impact filtration efficiency. One-layer mask blocks 60% particles from trumpet with little sound quality impact.