Here we look into the spread of aerosols indoors that may potentially carry viruses. Many viruses, including the novel SARS-CoV-2, are known to spread via airborne and air-dust pathways. From the literature data and our research on the propagation of fine aerosols, we simulate herein the carryover of viral aerosols in indoor air. We demonstrate that a lot of fine droplets released from an infected person’s coughing, sneezing, or talking propagate very fast and for large distances indoors, as well as bend around obstacles, lift up and down over staircases, and so on. This study suggests equations to evaluate the concentration of those droplets, depending on time and distance from the source of infection. Estimates are given for the safe distance to the source of infection, and available methods for neutralizing viral aerosols indoors are considered.

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Results of research into the evolution of disperse characteristics and concentration of an aerosol during its sedimentation by high-frequency ultrasound, are reported herein. Plots of the aerosol particles concentration versus time are given. The impact of ultrasonic vibrations on a medium-sized aerosol is shown to considerably accelerate its sedimentation due to the particle coagulation. The insertion of an additional dispersed phase (water droplets into a solid-phase aerosol) accelerates the sedimentation as well.

The harmful effect on the health of superfine dust in industry is a serious problem. An especially important and complex task is the development of new methods for sedimentation of dust particles with a characteristic size of less than 10 μm. The solution offered by the authors involves a combined method of impact on industrial dust using highfrequency acoustic fields and spraying of a superfine water aerosol. Acoustic radiation sources are successfully applied to cleaning rooms from dust having fairly large particle sizes (10 μm and larger). The sedimentation of fine aerosols (particle diameter of 1-10 μm) is a more complicated challenge. The paper is devoted to substantiation of the acoustic sedimentation method for such aerosols. Good results were achieved when additional disperse phase was applied together with the ultrasonic source. Calculation results according to the mathematical model for coagulation and sedimentation, based on Smoluchowski's equation, taking into account evaporation of liquid droplets, are given. Results of the experimental and theoretical study of the processes of acoustic sedimentation of superfine aerosols are presented. Recommendations are offered for the use of sources of ultrasonic radiation and sprayers of water aerosol for optimum removal of dust from workplace air.