The ultimate aim of sustainability in buildings gained an additional new dimension as the start of the year 2020 saw a rapid worldwide spread of the infectious disease caused by a coronavirus named COVID-19 . There is evidence that, in addition to person to person contact, the disease transmission occurs through airborne droplets/aerosols generated by breathing, speaking, coughing or sneezing . For that reason, building heating, ventilating and air conditioning systems can play an important role, as they may both contribute as well as reduce the transmission risk . However, there is insufficient understanding of the movement of infectious aerosols in buildings . This article introduces a method of bottom-up emergent modelling of the movement of infectious aerosols in internal space using a physics engine, and reports on simple simulation experiments . The results show that the smallest droplets that are large enough to contain the virus can be suspended in the air for an extended period of time; that turbulent air flow can contribute to the infectious aerosols remaining in the room; and that unidirectional air flow can contribute to purging the room of the infectious aerosols . The model introduced in this article is a starting point for further development and for increasing our understanding of the movement of infectious aerosols in buildings, and thus for increased sustainability of building design.