Seminar

Abstract

The airborne and short-range droplet routes of transmission of the SARS-CoV-2 virus are both considered to be important modes of transmission. Droplets are frequently designated to be of a size >5 micrometres in diameter; aerosol particles responsible for airborne transmission are of respirable size and smaller than 5 micrometres. In this talk, we will explore how physical chemistry can help us understand the properties of these colloidal systems and modes of transmission. We will describe recent measurements comparing aerosol and droplet emissions and size distributions from people singing and playing musical instruments compared to speaking, breathing and coughing, considering the possible associated risk. We will also explore the possibility of aerosol generation in various medical procedures. Aerosol and droplet size, composition and moisture content are dynamic with both drying rapidly once exhaled from the highly humid respiratory tract and we will review the interplay of dynamic and equilibrium properties in governing the distance of transmission of droplets and the phase of aerosol particles that remain suspended. Finally, we will introduce a new technique to study the survival of the SARS-CoV-2 in the aerosol phase and how infectivity depends on environmental factors such as relative humidity and temperature.

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Professor Jonathan Reid received his PhD at the University of Oxford in 1997, and completed his postdoctoral research at the University of Colorado Boulder. After a lectureship position at the University of Birmingham, he joined the faculty of the Physics Department at the University of Bristol in 2004. He has received the Royal Society of Chemistry Corday-Morgan medal, co-chairs the International Workshop on the Physical Chemistry of Aerosols, and is president of the Aerosol Society of the UK and Ireland.