Experimental Investigation of Aerosol and CO Dispersion for Evaluation of COVID-19 Infection Risk in a Concert Hall.

The dispersion of small aerosols in a concert hall is experimentally studied for estimating the risk of infection with SARS-CoV-2 during a concert. A mannequin was modified to emit an air stream containing aerosols and CO. The aerosols have a size distribution with a peak diameter (δ) close to 0.3 µm and a horizontal initial particle velocity (vp,x) of 2.4 m/s. The CO-concentration (c) emitted simultaneously is 7500 ppm. It is investigated, if the spatial dissipation of aerosols and CO can be correlated. This would allow the use of technically easier CO measurements to monitor compliance with aerosol concentration limits. Both aerosol and CO concentrations are mapped by different sensors placed around the mannequin. As a result, no significant enrichment of aerosols and CO was obtained outside a radius of 1.5 m when the fresh air ventilation in the concert hall has a steady vertical flow with a velocity of vg,z=0.05 m/s and the installed ventilation system was operating at an air change rate per hour (ACH) of 3, corresponding to an air exchange rate of 51,000 m/h. A Pearson correlation coefficient of 0.77 was obtained for CO and aerosol concentrations measured simultaneously at different positions within the concert hall.