Simple Safety Measures Reduce COVID-19 Music Transmission | CU Boulder today

Banner image: Music students practice safe and secure COVID protocols in Professor Don McKinnney’s Wind Symphony class at CU Boulder College of Music in the fall semester of 2020 (Photo credit: Glenn Asakawa / CU Boulder)

As the COVID-19 pandemic swept the world in 2020, musicians around the world desperately searched for answers to two pressing questions: Can playing a musical instrument transmit COVID-19? And if so, what can be done?

Today, midway through 2021, the first official research results are available, and that’s good news: the show can go on.

Published today in the journal ACS Environment Au, researchers at the University of Colorado at Boulder and the University of Maryland found that while playing musical instruments can emit the same levels of potentially COVID-laden airborne particles as singing , simple security measures, such as instrument masking, social distancing, and the implementation of time limits, significantly reduce this risk.

Graduate student Tehya Stockman places a homemade bell made of medical mask material to test the effectiveness of aerosol reduction in Shelly Miller’s Mechanical Engineering Lab on the CU Boulder Campus. (Credit: Glenn Asakawa / CU Boulder)

“COVID has shown people that aerosol transmission of respiratory disease is something that happens. But just because it goes into the air doesn’t mean everyone is going to get this disease. We have found that there are ways to mitigate these aerosols in a space and ways to reduce your risk, ”said Tehya Stockman, lead author of the article and graduate student in mechanical engineering.

This research began in earnest in 2020 at CU Boulder and the University of Maryland to find out whether playing musical instruments carried the same risks of transmitting COVID-19 as singing. While no outbreaks have been reported in instrumental ensembles, these published findings echo researchers’ initial assumptions and recommendations that were eagerly accepted at the onset of the pandemic by musicians and performing groups around the world.

“I want to salute the courage of the music directors and teachers to go ahead and follow our suggestions in the face of all this adversity, fear and worry,” said Shelly Miller, co-author of the study. and professor of mechanics and environmental engineering. “It really meant a lot to us because they trusted our very good research methods, our researchers, and the science changing as it goes from: we don’t know to, find out , to OK — now we know that. ”

These results do not only apply to the specific musical applications in which they were tested, they also confirm that masking works as an effective attenuation technique, and that ventilation and social distancing are important in reducing transmission, a Miller said. Miller said she hopes these findings will inspire more of a paradigm shift focused on mitigation and ventilation to reduce airborne transmission of infectious diseases.

Mitigation issues

The researchers tested three attenuation strategies on a variety of wind, reed and brass instruments, as well as with two singers and an actor. They evaluated these strategies, different performance times, and the differences between indoor and outdoor locations by measuring aerosols, carbon dioxide levels, and visualizing airflow using various modeling techniques.

First, they discovered that masks work, even on instruments, and that the quality of the filter material and their fit are important. Masks worn securely over a singer’s mouth and nose, as well as bell covers (made of MERV13 filter material) placed on the ends of the instruments dramatically reduced the speed and amount of particles produced by both sources.

For wind and reed instruments, they found that the amount of air escaping from keyholes does not significantly contribute to increased risk. This means that clarinetists and flautists do not need to place a bag around their instrument to play safely.

Second, the time spent together matters. To reduce the risk (to 10% risk of transmission), instrumentalists should spend less than 30 minutes indoors and less than 60 minutes outdoors playing together at a time. Regardless of social distance, “the risk of infection increases continuously with duration, regardless of distance from the singer or player,” the researchers found.

They also found that spacing pays off: leaving several meters of distance between players and singers reduces aerosol concentrations, which are highest the closer to each person who produces them. And while playing outdoors is best, a layered approach with all the other mitigation measures makes indoor play much safer.

Finally, no plexiglass or face shield is necessary. Airborne particles that transmit COVID-19 can easily bypass these barriers and mix with room air.

Quantification of carbon dioxide

French horns with bell covers

CU Boulder graduate Maddie Levinson began sewing COVID-friendly French horn blankets for school group programs across the state in 2020. Published research now confirms that using high-quality bell blankets , MERV13 filter material dramatically decreases the speed and COVID-laden particles produced from musical instruments. (Credit: Maddie Levinson)

So how can a musician or audience member now know that it is safe to attend a concert?

Carbon dioxide has been shown to be an excellent indicator of how well ventilated – or not – an indoor space is, and therefore its level of risk of catching COVID-19.

But in this study, the researchers showed that when someone wears a mask, carbon dioxide passes through the mask with the air that a person exhales, but the particles that can carry the virus get stuck. This means that when someone puts on a mask or a bell, emissions of carbon dioxide continue, but emissions of particles (which could carry the virus) are reduced.

“The concentration of carbon dioxide is a measure of the ventilation in the room. But if everyone is wearing a mask, the carbon dioxide in that room is still going to be high, but the respiratory droplets that can contain the virus are going to be much lower, ”Marina Vance, study co-author and assistant professor to the Department of Mechanical Engineering and the Environmental Engineering program. “So in this case, it’s not a direct representation of your risk.”

So, if a concert hall required that all members of the public wear masks and that all performers place a bell on their instrument, the risk of COVID transmission in that room would be reduced, even if the measured carbon dioxide levels were measured. are high. But carbon dioxide remains an excellent indicator of risk inside restaurants, where most people are not masked and often speak loudly.

Such a direct application of this research to real life scenarios was an extremely rewarding experience for Vance and the other researchers.

“The best part of the study was that all this technical knowledge and all this scientific knowledge was translated almost in real time and ended up in the hands of the people who needed it most. I’ve never been a part of anything like this, ”Vance said. “It was scary, exciting and important at the same time.”

The Safe Return of Music

When principal author Stockman learned to play the clarinet years ago, she did not do so in an attempt to advance scientific research. But her personal musical experience kept the work moving quickly, as she performed lab calibration tests on her own during the pandemic.

She understands the frustrations of musicians who may need to follow these protocols. She also knows how important it is to keep people safe.

“What we’ve shown is that there are easy steps you can take to keep life relatively normal and you don’t have to fear the air,” Stockman said.

This sentiment is shared by co-authors Mark Spede, national president of the College Band Directors National Association and director of groups at Clemson University, and James Weaver, director of performing arts and sports of the National Federation of Associations. from state high schools, who point out that the mitigation strategies tested in this study can be implemented not only during the persistent COVID-19 pandemic, but in the face of any future pathogens that may arise.

“While we may not know how the end of the pandemic will unfold, this important study has enabled performing arts educators to advocate for the safe return of live music to the classroom,” said Spede.

This research was conducted in partnership and collaboration with the National Federation of State High School Associations and the College Band Directors National Association.

Other authors of this publication include: Abhishek Kumar, Lingzhe Wang, Sameer Patel, Darin Toohey, and Jean Hertzberg of CU Boulder; and Shengwei Zhu, Don Milton and Jelena Srebric of the University of Maryland.