Experimental measurement of respiratory particles dispersed by wind instruments and analysis of the associated risk of infection transmission

Large Particle Emissions from Human Vocalization and Playing of Wind Instruments

“…Results show that, despite the large interparticipant variability, distinct differences were evident between the emission rates for the vocalization (singing and talking) and instrument playing (brass and woodwind instruments) categories, with vocalization producing on average 19.8 times (95% CI: 12.3, 31.8) higher emission rates than instrument playing (see Table S3 for model output and Figure for graphical results). These results were similar to Schlenczek et al, who reported that wind instruments produce 30–600 times lower concentrations for d p > 10 μm compared with talking and singing . Within the categories of vocalization and instrument playing, pairwise comparison testing indicated nonsignificant differences between talking and singing ( p = 0.57) and between brass and woodwind instruments ( p = 0.50); see Table S5 for model results.…”

“…Schlenczek et al used a holographic setup to detect large particles produced by wind instruments, and although they found no evidence of large particles emitted from the instrument bell, they detected a substantial amount of d p > 35 μm particles emitted from the instrument mouthpiece, suggesting particle filtering by the instrument tubing as a main factor. 9 This filtering of large particles on the inner tubing of the instrument is supported by Viala et al who employed a computational fluid dynamics simulation for a clarinet and reported that particles > 50 μm will deposit inside the instrument before being emitted from the bell. 10 From a mass standpoint, the differences in emission rates found in this study between performance set types within the categories (i.e., talking vs singing in the vocalization category) were also insignificant.…”

“…Schlenczek et al reported similar findings (albeit with a small sample size) in their study where the super-emitters for breathing were not the same as the super-emitters for instrument playing. 9 Future studies should utilize many replicate samples from the same individuals to gather a more statistically robust data set to better understand if super-emitting tendencies for individuals are common across activity types and examine the temporal variability among these individuals. Results show that, despite the large interparticipant variability, distinct differences were evident between the emission rates for the vocalization (singing and talking) and instrument playing (brass and woodwind instruments) categories, with vocalization producing on average 19.8 times (95% CI: 12.3, 31.8) higher emission rates than instrument playing (see Table S3 for model output and Figure 2 for graphical results).…”

“…The COVID-19 pandemic has motivated a growing body of research on human respiratory aerosol generation and disease transmission associated with activities like talking, singing, and playing musical instruments. − To date, most of this research has focused on smaller particles (aerodynamic particle diameter, d p < 10 μm), which are relatively easy to count and size using conventional instruments like optical particle counters and aerodynamic particle sizers . Smaller particles are important because they can remain airborne for hours and travel distances beyond typical “close-contact” thresholds used in disease control guidance (∼2 m) and have been shown to transmit infectious pathogens in air. , However, larger particles ( d p > 10 μm) are also emitted during the same respiratory aerosol generation processes.…”

“…Conventional aerosol counting and sizing instruments are limited in their ability to measure larger particles because such particles have a relatively high inertia in air (i.e., they experience high rates of aspiration and transmission losses during sampling) . Open-path laser instruments have been used to size larger airborne particles, , but such measurements are considered semiquantitative, especially under turbulent flow conditions (e.g., during vocalization). For example, Stadnytskyi et al reported emissions rates of large and small particles emitted from 25 s of talking; however, these size-resolved results are considered semiquantitative because there was no effective way to equate scattered light intensity to particle size, since light intensity varied across the laser sheet.…”