Darchei Noam’s own Marianne Levitsky, an expert in industrial hygiene, will present an online tutorial on masks and ventilation for protection against COVID-19. Information will be provided on how COVID-19 can be transmitted in the air, and how you can select and fit masks to get the best protection possible. The session will also describe choices you can make about ventilation to help prevent transmission indoors. The presentation will be followed by a question and answer session.