Wind instruments don’t spit COVID more than speech: study
August 19, 2022 — Good news for music lovers and musicians alike: Wind instruments don’t seem to shed more COVID-19 particles than speech, according to a new study.
New research from the University of Pennsylvania, along with members of the Philadelphia Orchestra, has found that wind instruments do not spread COVID-19 particles further or faster than a human would during normal speech.
“We are probably one of the first studies to combine aerosol flow rate and concentration measurements to study aerosol dispersion from wind instruments,” says Paulo Arratia, PhD, professor of mechanical engineering and applied mechanics at the university, which conducted the study.
Arratia and his colleagues used a particle counter, humidifier, and green laser to visualize and measure how much and how quickly aerosols sprang from wind instruments (think brass and woodwind instruments) as members of the orchestra played their instrument continuously for almost 2 minutes. They measured the output of many instruments, including flutes, clarinets, trumpets and tubas.
The challenge was figuring out how far apart musicians could be to play their instruments without requiring a plexiglass barrier or risking the spread of COVID-19 to ensemble members or the audience, says Arratia.
The researchers created a fog-like environment near the opening of the instrument using an ultrasonic humidifier. A green laser illuminated the artificial fog. With so much moisture in the air and a light source streaming through, Arratia and the other researchers were able to measure the abundance and velocity of the aerosolized particles.
Most of the released particles were less than a micrometer thick, similar to what would occur with normal breathing and speaking.
The virus particles weren’t ejected from the opening of the wind instruments as violently as when a person coughs or sneezes, Arratia says. Indeed, the flow rate was less than 0.1 meters per second, almost 50 times slower than the speed of a cough or sneeze, which fluctuates between 5 and 10 meters per second, according to the study.
And the particles from most instruments only traveled about 6 feet before decaying to background airstream levels. Only two instruments in the study, the flute and the trombone, sent particles over 6 feet before the aerosol fell to undetectable levels. Therefore, keeping woodwind and brass players 6 feet apart can also help reduce the spread and contamination of COVID-19 particles during live performances, Arratia says.
“During the pandemic, orchestras spread out their musicians and used plexiglass barriers to protect against aerosols, which was not ideal for sound quality,” he says. Musical pieces had to be adapted to exclude wind and brass instruments, ad venues have postponed or canceled many concerts.
Smaller community orchestras have faced unique challenges as they attempt to follow the COVID-19 protocols put in place by larger orchestras without the same financial resources.
“We don’t have the resources that large orchestras had, there was no way to build plexiglass shields around our musicians,” says Ivan Shulman, MD, music director of the Los Angeles Doctors Symphony Orchestra. “In fact, other than a disconcerting sound, it only redispersed the droplets, at least as far as the information we saw was concerned.”
To ensure the safest environment for all, Shulman, an assistant clinical professor of surgery at the University of California, Los Angeles, chose pieces like Aaron Copland’s. Marching Band for the Common Man, a drum and brass composition that allowed players to be widely spaced out. All members except the wind and brass section wore masks at every rehearsal and concert, and everyone had to be vaccinated.
“Some orchestras only tested all the wind instruments, before each rehearsal,” Shulman explains. “We couldn’t afford to do it, but with more tests available, we thought we’d do it when we start again in September.”
While Shulman may not have been able to assess how his instruments propagate the particles, his orchestra used a carbon dioxide monitor as a proxy for ventilation in the rehearsal space.
“The evidence we saw was that if you kept the CO2 concentration below about 1,100 parts per million, you were safe,” he says. “We never found that we were approaching worrying levels.”
The new findings are reassuring, Shulman says.
“The concern I have is even with that, in an orchestral setting, how many people want to be near the people who are talking? Would they prefer to be further away? We still have to think about how close people are.”
Nonetheless, the COVID-19 protocols are worth replaying.
“Just being able to play together was enough to allay people’s fears that it was worth it,” Shulman says. “We just want to maintain and create a safe space for everyone.”