Aerosol emissions from wind instruments: effects of performer age, sex, sound pressure level, and bell covers

Abstract

Aerosol emissions from wind instruments are a suspected route of transmission for airborne infectious diseases, such as SARS-CoV-2. We evaluated aerosol number emissions (from 0.25 to 35.15 μm) from 81 volunteer performers of both sexes and varied age (12 to 63 years) while playing wind instruments (bassoon, clarinet, flute, French horn, oboe, piccolo, saxophone, trombone, trumpet, and tuba) or singing. Measured emissions spanned more than two orders of magnitude, ranging in rate from < 8 to 1,815 particles s^-1, with brass instruments, on average, producing 191% (95% CI 81-367%) more aerosol than woodwinds. Being male was associated with a 70% increase in emissions (vs. female; 95% CI 9-166%). Each 1 dBA increase in sound pressure level was associated with a 28% increase (95% CI 10-40%) in emissions from brass instruments; sound pressure level was not associated with woodwind emissions. Age was not a significant predictor of emissions. The use of bell covers reduced aerosol emissions from three brass instruments tested (trombone, tuba, and trumpet), with average reductions ranging from 53 to 73%, but not for the two woodwind instruments tested (oboe and clarinet). Results from this work can facilitate infectious disease risk management for the performing arts.

Figure 1

Boxplots of aerosol number emission rates (0.25–35.15 μm size range) by instrument class and type, including vocalists. Instruments are ordered by median emission rate with participant data as open circles; boxes delineate the inter-quartile range (IQR) and whiskers extend to 1.5⋅IQR or the data minimum. The dashed horizontal line represents a method quantification limit (8.3 particles s⁻¹). Data are background corrected.

Figure 2

Boxplots of aerosol number emission rates (0.25–35.15 μm size range) by instrument class and participant sex (assigned at birth). Box limits delineate the inter-quartile range (IQR) with median values at center; whiskers extend to 1.5⋅IQR or the data minimum. The dashed horizontal line represents a method quantification limit (8.3 particles per second). All data are background corrected.

Figure 3

Correlation between instrument sound pressure level and aerosol number emission rates (0.25–35.15 μm size range), stratified by instrument class. All data are background corrected; correlations consider only measurement data above method detection limit.

Figure 4

Effect of bell covers on reducing aerosol number emissions (0.25–35.15 μm size range) from instruments. (A) Participant-specific changes in CO₂-normalized aerosol number concentration with bell covers (each line represents a pair of measurements for a participant with and without a bell cover). (B) Average percent reduction in emissions with 95% confidence intervals. Data are background corrected and restricted to instruments with n ≥ 3 measurement pairs.