Pollstar (01/14/21) Gottfried, Gideon

A study performed in November at Germany's Konzerthaus Dortmund concert hall probed the spatial dispersion of aerosols and CO2, to determine that the venue's central ventilation system and the wearing of face masks significantly lowers aerosol and CO2 contamination, "to the point that full occupancy of the concert hall would theoretically be conceivable." However, the authors still advise a checkerboard auditorium layout that reduces capacities to around 50%, in order to guarantee sufficient airflow in hallways and foyers. Among the study's findings was that a mask and a sufficient supply of fresh air via the existing ventilation and air conditioning system meant test aerosols' influence on any of the neighboring places from an emitting test person was practically insignificant. Moreover, the large room volume already ensures strong dilution of polluted aerosols, which was effectively removed in all areas and cannot accrue due to the supply and extraction air operation of the ventilation system without recirculation function. Meanwhile, more people in the auditorium does not interfere with the upwards air flow, but in fact promotes it through additional thermal effects. "The past months have shown that politicians need a scientifically sound basis for decision making," said Konzerthaus Dortmund Artistic Director Raphael von Hoensbroech. "With our study, we want to contribute, to help ensure that concert halls and theaters can again admit sufficient audiences when they reopen."

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