Aerosol emission rates from playing wind instruments – Implications for COVID-19 transmission during music performance

Abstract

BackgroundThe pandemic of COVID-19 led to exceeding restrictions especially in public life and music business. Airborne transmission of SARS-CoV-2 demands for risk assessment also in wind playing situations. Previous studies focused on short-range transmission, whereas long-range transmission has not been assessed so far.Methods and findingsWe measured resulting aerosol concentrations in a hermetically closed cabin of 20 m3 in an operating theatre from 20 minutes standardized wind instrument playing (19 flute, 11 oboe, 1 clarinet, 1 trumpet players). Based on the data, we calculated total aerosol emission rates showing uniform distribution for both instrument groups (flute, oboe). Aerosol emission from wind instruments playing ranged from 7 ± 327 particles/second (P/s) up to 2583 ± 236 P/s, average rate ± standard deviation. The analysis of the aerosol particle size distribution showed that about 70 − 80% of emitted particles had a size ≤ 0.4 µm and thus being alveolar. Masking the bell with a surgical mask did not reduce aerosol emission. Aerosol emission rates were higher from wind instruments playing than from speaking and breathing. Differences between instrumental groups could not be found, but high interindividual variance as expressed by uniform distribution of aerosol emission rates.ConclusionsOur findings indicate that aerosol emission depends on physiological factors and playing techniques rather than on the type of instrument, in contrast to some previous studies. Based on our results, we present risk calculations for long-range transmission of COVID-19 for three typical woodwind playing situations.

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

“…The emitted particle number concentration from the trumpet measured by Stockman et al (2021) was 3 times lower compared to He et al (2021). Emitted particle number concentration shown in Firle et al (2021) is also higher for playing flute or oboe compared to speaking. In all of the studies mentioned above, and also in Brosseau et al (2022), the conclusion was drawn that the highest number density of emitted particles from wind instruments is <1 µm.…”

“…However, the fact that wind instruments also release respiratory particles (see e.g. Lai et al, 2011;He et al, 2021;Kähler and Hain, 2020;Parker and Crookston, 2020;Spahn et al, 2021;Stockman et al, 2021;Abraham et al, 2021;McCarthy et al, 2021;Firle et al, 2021;Gantner et al, 2022) indicates that band or orchestra rehearsals or concerts are also associated with an enhanced risk of airborne infection transmission (hereafter called "infection risk"). Because of this potential risk, most forms of live music events were forbidden in most of 2020 in Germany and also other countries.…”

“…Furthermore, these studies (except for Firle et al, 2021) used an Aerodynamic Particle Sizer (APS) from TSI Inc. as the primary aerosol size spectrometer, which nominally measures the aerodynamic diameter of particles in a size range from 0.5 to 20 µm. However, it cannot detect smaller than 0.5 µm that may include a significant number of particles containing ∼0.1 µm SARS-CoV-2 virions and, as pointed out in Bagheri et al (2021a) and other studies (e.g.…”

“…The well-mixed room is recently used by several investigations (e.g. Buonanno et al, 2020;Nordsiek et al, 2021;Miller et al, 2020;Jimenez, 2020;Bagheri et al, 2020;Firle et al, 2021;Kriegel et al, 2022). Miller et al (2020) as well as Kriegel et al (2022) determined the emission rate of pathogen copies from retrospective analyses of superspreading events.…”

“…To give a reasonable estimation on the efficacy of infection mitigation measures, the relationship between particle size and number concentration of pathogen copies needs to be known. The risk calculation done by Firle et al (2021) was based on a constant conversion factor from pathogen copies to particle number concentration within a specified diameter range. Numerical simulations carried out by Stockman et al (2021) have shown that the well-mixed room assumption is reasonable for indoor spaces of 18 m 2 area and 63 m 3 volume if the susceptible is not standing downwind of the infectious (i.e.…”