Characterization of the utility of three nebulizers in investigating infectivity of airborne viruses

Laboratory-generated bioaerosols are widely used in aerobiology studies of viruses, however few comparisons of alternative nebulizers exist. We compared aerosol production and virus survival for a Collison nebulizer, vibrating mesh nebulizer (VMN), and hydraulic spray atomizer (HAS). We also measured the dry size distribution of the aerosols produced, calculated the droplet sizes before evaporation and the dry size distribution from normal saline solution. Dry count median diameters of 0.25, 0.63 and 0.76 µm were found for normal saline from the Collison nebulizer, VMN and HSA, respectively. The volume median diameters were 2.91, 3.2 and 2.43 µm, respectively. The effect of nebulization on the viability of two influenza A viruses (IAVs) (H1N1, H3N2) and human rhinovirus (HRV)-16, was assessed by direct nebulization into an SKC Biosampler. The HSA had least impact on surviving fractions (SFs) of H1N1 and H3N2 (89±5%, 94±3%), followed by the Collison nebulizer (82±2%, 82±3%). The VMN yielded SFs of 78±2% and 76±2%, respectively. Conversely, for HRV-16, the VMN produced higher SFs (86±15%). Our findings indicate that although the VMN had the greatest impact on IAV survival, it produced higher aerosol concentrations within the airborne-size range making it more suitable where high aerosol mass production is required. Importance Viral respiratory tract infections cause millions of lost days of work and physician visits globally, accounting for significant morbidity and mortality. Respiratory droplet and droplet nuclei from infected hosts are the substantial potential carriers of such viruses within indoor environments. Laboratory-generated bioaerosols are applied in understanding the transmission and infection of viruses, simulating the physiological aspects of bioaerosol generation in a controlled environment. However, little comparative characterization exists for nebulizers used in infectious disease aerobiology, including Collison nebulizer, Vibrating mesh nebulizer, and hydraulic spray atomizer. This study characterized the physical features of aerosols generated by laboratory nebulizers, and their performance in producing aerosols at a size relevant to airborne transmission used in infectious disease aerobiology. We also determined the impact of nebulization mechanisms of these nebulizers on the viability of human respiratory viruses, including IAV H1N1, IAV H3N2 and HRV-16.