Pantelic J, Tham K W, Licina D
School of Public Health, Maryland Institute for Applied Environmental Health, University of Maryland at College Park, College Park, MD, USA.
Department of Building, School of Design and Environment, National University of Singapore, Singapore, Singapore.
Indoor Air. 2015 Dec;25(6):683-93. doi: 10.1111/ina.12187. Epub 2015 Feb 16.
The inhalation intake fraction was used as an indicator to compare effects of desktop personalized ventilation and mixing ventilation on personal exposure to directly released simulated cough droplets. A cough machine was used to simulate cough release from the front, back, and side of a thermal manikin at distances between 1 and 4 m. Cough droplet concentration was measured with an aerosol spectrometer in the breathing zone of a thermal manikin. Particle image velocimetry was used to characterize the velocity field in the breathing zone. Desktop personalized ventilation substantially reduced the inhalation intake fraction compared to mixing ventilation for all investigated distances and orientations of the cough release. The results point out that the orientation between the cough source and the breathing zone of the exposed occupant is an important factor that substantially influences exposure. Exposure to cough droplets was reduced with increasing distance between cough source and exposed occupant.
The results from this study show that an advanced air distribution system such as personalized ventilation reduces exposure to cough-released droplets better than commonly applied overhead mixing ventilation. This work can inform HVAC engineers about different aspects of air distribution systems’ performance and can serve as an aid in making critical design decisions.
吸入摄取分数被用作一个指标，以比较桌面式个性化通风和混合通风对个人暴露于直接释放的模拟咳嗽飞沫的影响。使用咳嗽机在1至4米的距离模拟从热人体模型的正面、背面和侧面释放咳嗽。用气溶胶光谱仪在热人体模型的呼吸区内测量咳嗽飞沫浓度。使用粒子图像测速技术来表征呼吸区内的速度场。对于所有研究的咳嗽释放距离和方向，与混合通风相比，桌面式个性化通风显著降低了吸入摄取分数。结果指出，咳嗽源与暴露居住者呼吸区之间的方向是一个显著影响暴露的重要因素。随着咳嗽源与暴露居住者之间距离的增加，对咳嗽飞沫的暴露减少。
本研究结果表明，诸如个性化通风这样的先进空气分配系统比常用的顶部混合通风能更好地减少对咳嗽释放飞沫的暴露。这项工作可以让暖通空调工程师了解空气分配系统性能的不同方面，并有助于做出关键的设计决策。
