Brass wind instruments with long sections of cylindrical pipe, such as trumpets and trombones, sound “brassy” when played at a fortissimo level due to the generation of a shock front in the instrument. It has been suggested that these shock fronts may increase the spread of COVID-19 by propelling respiratory particles containing the SARS-CoV-2 virus several meters due to particle entrainment in the low pressure area behind the shocks. To determine the likelihood of this occurring, fluorescent particles, ranging in size from 10–50 lm, were dropped into the shock regions produced by a trombone, a trumpet, and a shock tube. Preliminary results indicate that propagation of small airborne particles by the shock fronts radiating from brass wind instruments is unlikely.
T. Moore and A. Cannaday, "Do 'brassy' sounding musical instruments need increased safe distancing requirements to minimize the spread of COVID-19?" Journal of the Acoustical Society of America Issue 148, no.4 (October 2020): 2096-2099. https://doi.org/10.1121/10.0002182
Journal of the Acoustical Society of America