Measurement of small droplet aerosol concentrations in public spaces using handheld particle counters

We investigate the role of aerosols in the transmission of SARS-CoV-2 in public spaces. Direct measurement of aerosol concentrations however has proven technically difficult; we propose the use of handheld particle counters as a novel and easily applicable method to measure aerosol concentrations. This allow us to perform measurements in typical public spaces, each differing in volume, number of people and ventilation rate. These data are used to estimate the relation between aerosol persistence time and the risk of infection with SARS-CoV-2.