ASHRAE offers a free webinar with Indoor Air Quality expert William Bahnfleth, PhD, PE, providing an overview of ultraviolet germicidal irradiation (UVGI) to reduce risk of infectious disease transmission by inactivating pathogens in the air and on surfaces. Topics include fundamentals of microbial response to UVGI, inactivation rate constants of microorganisms and their importance to system design, germicidal light sources and their operating characteristics, UVGI system types and their applications in air, in occupied spaces, and for unoccupied surface decontamination.