Just like coughing, sneezing, talking and singing, and playing wind instruments, particularly those in the brass section can spread respiratory particles that may carry the COVID-19 virus, according to a study.

Early in the pandemic, researchers at Colorado State University teamed up with musicians and performers to try and quantify respiratory particle emissions from various activities like singing and music playing. They were seeking to provide insight into just how much performance arts could spread COVID-19 and inform safety measures moving forward.

The findings, published in the journal Scientific Reports, showed that brass instruments, on average, produced 191 per cent more aerosols than woodwinds. Being male was also associated with a 70 per cent increase in emissions from instrument-playing, probably due to lung size and capacity, the researchers think.

For the study of the instruments, they had 81 volunteer performers of both sexes and of varied ages between 12 and 63. The volunteers played wind instruments including the bassoon, clarinet, French horn, oboe, piccolo, saxophone, trombone, trumpet, and tuba.

The louder playing of brass instruments was associated with higher particle counts, but the louder playing of woodwinds didn't increase emissions.

The researchers also took measurements with performers using bell covers in an attempt to mitigate the particle spread, which seemed to work. The use of bell covers reduced emissions from trombone, tuba and trumpet players, with average reductions of 53-73 per cent, but not for oboe or clarinet.

Professor John Volckens, a mechanical engineer and aerosols expert at CSU likened the bell covers to blue surgical masks for instruments good, but not great in terms of limiting spread.

"The data suggest that masks and bell cover to cut down half to 75 per cent of particles coming out of the mouth or instrument," Volckens said. "And the reason blue surgical masks or bell covers don't work better is that they're just not a tight fit. These devices don't achieve an N95 level of protection."

He also said that "if we could make N95s for instruments", it would likely help reduce emissions from brass instruments, but not from woodwinds, because those instruments have too many escape holes before the bell. A single-exit instrument like a trumpet is easier to control with protective measures, the researchers said.