The dispersion of aerosols was studied experimentally in several concert halls to evaluate their airborne route and thus the risk of SARS-CoV-2 spreading. For this, a dummy is used that emits simulated human breath containing aerosols with a mean diameter of 0.3 µm, and horizontal exhalation velocity of v =2.4 m/s measured 10 cm in front of the mouth as well as CO2. Aerosol and CO2 concentration profiles were mapped using sensors placed around the dummy. No substantial enrichment of aerosols and CO2 was found at adjacent seats, provided that: (1) there are floor displacement outlets under each seat enabling a minimum local fresh air vertical flow of vv =0.05 m/s, (2) the air exchange rate (ACH) constitutes more than 3 h-1, and (3) the dummy wears a surgical face mask. Knowledge of dispersion of viral droplets by airborne routes in real environment helps to establish risk assessment when re-opening concert halls and theaters after pandemic lock down.
Viral aerosol transmission of COVID-19 from simulated human emission in a concert hall