Building and Environment will host a series of free webinars on COVID-19 Control. The third webinar of the series will feature 2 presentations from experts in the field on the following topics: Continuum of airborne transmission of respiratory infection, and implication to ventilation requirements, presented by Prof. Yuguo Li, Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China. The second presentation will be on the Occupational exposure risk of healthcare workers during the COVID-19 pandemic, presented by Prof. Li Liu, Department of Building Science, Tsinghua University, China.