New German Study Lays Out Conditions for Safely Holding Indoor Concerts

A new study, commissioned by a concert venue on Dortmund, Germany and conducted by the Fraunhofer Heinrich Institute Goslar and measurement specialist firm ParteQ, has reported it results on the issues relating to the dispersion of aerosols and CO2 in a concert hall environment. The findings from the study, which was conducted in cooperation with the German Environment Agency, suggest that, under certain circumstances, it is possible to safely hold indoor concerts even during a pandemic.

A statement from Konzerthaus Dortmund notes that this is "the first published study to provide experimental data for evaluating the coronavirus infection risk during concert halls visits with textensive measuresments being taken in the Konzerthaus Dortmund auditorium and foyers on November 2 - 3 and 20, 2020. The study shows that the risk of transmission and infectious agents by aersol transmission can almost be excluded, especially in the auditorium."

The release further states, "Utilization of the existing central ventilation system and the wearing of face asks greatly reduces aerosol and CO2 pollution, to the point that full occupancy of the concert hall would theoretically be conceivable." Nevertheless, it goes on to recommend a "checkerboard auditorium layout" is current recommended, which means audiences at 50% of capacity. Still, the release asserts "the study can also be used to make similar statements for other similarly sized concerts halls and theatres."

The key findings are:

*"With a mask, and with a sufficient supply of fresh air via the existing ventilation and air conditioning system, there was practically no influence of test aerosols on any of the neighboring places from an emitting test person during the tests.

*"The large room volume already ensures a strong dilution of contaminated aero- sols, and due to the supply and extraction air operation of the ventilation system without recirculation function, aerosols are effectively removed in all areas and cannot accumulate.

*"Without a mask, the seat directly in front should be kept free. With the remaining neighboring seats, infection is very unlikely. A checkerboard seating arrangement of the auditorium is recommended in any case.

*"Greater number of people in the auditorium does not disturb the upwards air flow, but rather promotes it through additional thermal effects.

*"Wearing masks is always necessary in corridors, in break areas, and in the foy-ers, as the ventilation system works differently here than in the auditorium (where air escapes through the ceiling) and where close contact cannot be ruled out. During breaks all doors to the auditorium should remain open to allow for additional cross- flow ventilation.

*"The concert hall cannot trigger a superspreading event with the existing ventilation in place (with a complete air exchange with fresh, outside air every 20 minutes).

*"CO2 measurements during operation can help to better assess the dispersion of air- borne particles in the auditorium.

Summing up, the report states "A reopening with at least 50% capacity in a checkerboard arrangement, with one seat free between each seated group, can be recommended on the basis of the study results, especially since the safety distances in the foyer areas and on routes in and out of the auditorium can be ensured. A lower occupancy rate would have no added value for infection control. From a hygiene perspective, once the overall infection figures have returned to a low level it would be conceivable to have a fully occupied auditorium at a later date, providing masks are worn. This could be backed up, for example, with model-based calculations."

The results are similar to another conductedin Halle, Germany this summer and reported on in the November issue of Lighting&Sound America. Many questions remain: Would US audiences tolerate being masked while attending performances? Would venues accept the liability risk of presenting performances while a pandemic continues to rage? Still the findings suggest that, once vaccines are widely disseminated, it will be possible to additionally protect audiences from infection -- which may speed the return to production in many sectors of the industry.