Singing, acting and playing certain musical instruments are all considered high risk activities because they force the performer to expel more particles.
Dr. John Volckens is a professor of mechanical engineering at Colorado State University who has been studying how these behaviors can impact particle emissions, and says that singing can cause someone to emit four times as many particles as talking or breathing.
“There’s good evidence to suggest that the vocal chords - the actual making of sound, that vibrational energy - is one of the culprits that releases particles out of your respiratory tract. So when you’re singing you are releasing particles constantly because you keep a constant pitch. When you’re talking you release a lot of particles as well, but there’s something about singing – it might be the frequency or the way your vocal chords are used or the volume – but we see a lot more emissions when people sing,” Dr. Volckens explained on KCBS Radio's "Ask An Expert" program.
Wind instruments appear to have the same effect as saliva flows into the instrument, which can then be expelled into the air.
Dr. Volckens says the amount of emissions is also highly dependent on the individual.
“We know that from one person to the next, the amount of particles that come out of your body when you’re talking or singing or even just breathing differs wildly. I’m not talking about 10% more from one person to the next, I’m talking a factor of 10.”
One of the participants in Dr. Volcken’s study turned out to be a “super emitter.” When this person sang, his team recorded emissions equal to 22 people all talking at once.
But regardless of how much each person emitted while talking, Dr. Volckens says it is clear that singing and playing an instrument increases the amount of particles that are released, therefore increasing the risk of transmission.
Being able to perform safely is further complicated because most traditional music or theater performances happen in indoor spaces that are designed to allow sound to spread.
Volckens says while more research needs to be done on reducing risk, performing outdoors, thorough ventilation and filtration indoors and masks for singers and actors can help.