Events

Atmospheric & Environmental Chemistry Seminars

SARS-COV-2: Respiratory aerosols, droplets and airborne transmission

Jonathan Reid, Professor, University of Bristol

Nov 12, 2021
12:00 pm to 1:00 pm | Remote

Register Here: https://harvard.zoom.us/meeting/register/tJclcemvrj8qH9dd1MH0vBqTWW2ay0SUMJQK

Abstract

Aerosols of respirable size (<10um diameter) are exhaled when breathing, speaking and coughing and can transmit respiratory pathogens. Improved quantification of number and mass exhalation rates could support estimates of viral shedding and assessments of transmission risk. Previous studies report aerosol concentrations in an exhaled plume; we will present absolute exhalation rates from measurements of minute ventilation using cardiopulmonary exercise testing with exhaled particle concentrations. Measurements are made in a zero-background space to ensure all aerosols detected originate from the participant, reporting mass exhalation rates for children (aged 12-14) and adults (19-72) when breathing, speaking, singing and exercising. We will also report measurements of hygroscopic response of exhaled aerosol along with studies of evaporation rates and phase behaviour. 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. We will also report new measurements of the survival of SARS-COV-2 in aerosol using a novel single particle approach in a CL-3 laboratory, examining the dependence of infectivity on relative humidity and temperature.

Contact
Contact:

Zhen Qu

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