Department of Chemical Physics and Applied Thermodynamics, Córdoba University, Córdoba, Spain.
Indoor Air. 2012 Feb;22(1):64-76. doi: 10.1111/j.1600-0668.2011.00736.x. Epub 2011 Sep 11.
The level of exposure to human exhaled contaminants in a room depends not only on the air distribution system but also on people's different positions, the distance between them, people's activity level and height, direction of exhalation, and the surrounding temperature and temperature gradient. Human exhalation is studied in detail for different distribution systems: displacement and mixing ventilation as well as a system without mechanical ventilation. Two thermal manikins breathing through the mouth are used to simulate the exposure to human exhaled contaminants. The position and distance between the manikins are changed to study the influence on the level of exposure. The results show that the air exhaled by a manikin flows a longer distance with a higher concentration in case of displacement ventilation than in the other two cases, indicating a significant exposure to the contaminants for one person positioned in front of another. However, in all three cases, the exhalation flow of the source penetrates the thermal plume, causing an increase in the concentration of contaminants in front of the target person. The results are significantly dependent on the distance and position between the two manikins in all three cases.
Indoor environments are susceptible to contaminant exposure, as contaminants can easily spread in the air. Human breathing is one of the most important biological contaminant sources, as the exhaled air can contain different pathogens such as viruses and bacteria. This paper addresses the human exhalation flow and its behavior in connection with different ventilation strategies, as well as the interaction between two people in a room. This is a key factor for studying the airborne infection risk when the room is occupied by several persons. The paper only takes into account the airborne part of the infection risk.
室内空气中人体呼出污染物的浓度不仅取决于送风方式，还与人员的位置、人员之间的距离、人员的活动水平和高度、呼气方向以及周围的温度和温度梯度有关。针对不同的送风系统，如置换通风、混合通风和无机械通风系统，对人体呼气进行了详细研究。使用两个通过嘴部呼吸的热人体模型来模拟人体呼出污染物的暴露情况。改变人体模型的位置和距离，研究其对暴露水平的影响。结果表明，与另外两种情况相比，在置换通风条件下，人体模型呼出的空气流动距离更长，浓度更高，表明处于另一个人体模型前方的人会显著暴露于污染物中。然而，在所有三种情况下，源的呼气流都会穿透热羽流，导致目标人体前方的污染物浓度增加。在所有三种情况下，结果都显著依赖于两个热人体模型之间的距离和位置。
室内环境容易受到污染物暴露的影响，因为污染物很容易在空气中传播。人体呼吸是最重要的生物污染物来源之一，因为呼出的空气中可能含有不同的病原体，如病毒和细菌。本文研究了不同通风策略下人体呼气的流动及其行为，以及室内两个人之间的相互作用。这是研究当房间内有多人时，空气传播感染风险的关键因素。本文仅考虑了感染风险的空气传播部分。
