Scientists in Sweden also found that the louder and more powerful the song, the more likely the virus is to spread.
Researchers at Lund University in Sweden have found that singing has a high potential to spread droplets contaminated by the new coronavirus.
The discovery was published last month in the journal Aerosol Science and Technology.
“There are many reports about the spreading of Covid-19 in connection with choirs singing. Therefore, different restrictions have been introduced all over the world to make singing safer,” said Jakob Löndahl, associate professor of Aerosol Technology at Lund University
“So far, however, there has been no scientific investigation of the amount of aerosol particles and larger droplets that we actually exhale when we sing.”
To conduct the research, scientists looked at 12 healthy singers and two who tested positive for Sars-CoV-2.
The volunteers put on clean suits and entered a specially built chamber with filtered air.
Then, they had to sing a Swedish song known as “Bibbis pippi Petter”, which was repeated 12 times in two minutes, in a constant pitch. The same song was also repeated without the consonants, leaving only the vowels.
The researchers analyzed the number and mass of particles emitted by singers during breathing, talking, and different types of singing. The authors also investigated what happened when they sang wearing a face mask.
“We also carried out measurements of virus in the air close to two people who sang when they had Covid-19. Their air samples contained no detectable amount of virus, but the viral load can vary in different parts of the airways and between different people,” said Malin Alsved, co-author of the study. “Accordingly, aerosols from a person with Covid-19 may still entail a risk of infection when singing.”
Scientists have not only found that singing spreads many particles, but also that loud and consonant-rich singing considerably increases the amount of droplets emitted.
“Some droplets are so large that they only move a few decimetres from the mouth before they fall, whereas others are smaller and may continue to hover for minutes. In particular, the enunciation of consonants releases very large droplets and the letters B and P stand out as the biggest aerosol spreaders,” Alsved explained.
This does not mean that singing in choirs should be strictly prohibited from now on. According to experts, the risk of contamination decreases considerably when singers keep their distance from each other, follow good hygiene practices, are in a well-ventilated area, and wear a face mask.
“When the singers were wearing a simple face mask this caught most of the aerosols and droplets and the levels were comparable with ordinary speech,” Löndahl concluded.