Assessment of personal exposure to infectious contaminant under the effect of indoor air stability.

The objective of this study is to understand the effect of indoor air stability on personal exposure to infectious contaminant in the breathing zone. Numerical simulations are carried out in a test chamber with a source of infectious contaminant and a manikin (Manikin A). To give a good visual illustration of the breathing zone, the contaminant source is visualized by the mouth of another manikin. Manikin A is regarded as a vulnerable individual to infectious contaminant. Exposure index and exposure intensity are used as indicators of the exposure level in the breathing zone. The results show that in the stable condition, the infectious contaminant proceeds straightly towards the breathing zone of the vulnerable individual, leading to a relatively high exposure level. In the unstable condition, the indoor air experiences a strong mixing due to the heat exchange between the hot bottom air and the cool top air, so the infectious contaminant disperses effectively from the breathing zone. The unstable air can greatly reduce personal exposure to the infectious contaminant in the breathing zone. This study demonstrates the importance of indoor air stability on personal exposure in the indoor environment and provides a new direction for future study of personal exposure reduction in the indoor environment.