Airborne transmission of COVID-19 and mitigation using box fan air cleaners in a poorly ventilated classroom.
Airborne transmission of COVID-19 and mitigation using box fan air cleaners in a poorly ventilated classroom.
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DOI：
10.1063/5.0050058
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发表时间：
2021-05
期刊：
影响因子：
--
通讯作者：
Hong J
中科院分区：
文献类型：
--
作者：
He R;Liu W;Elson J;Vogt R;Maranville C;Hong J
许多室内场所，包括老旧的教室和办公室、监狱、无家可归者收容所等，这些地方通风欠佳，但资源有限，无法负担昂贵的通风升级或商业空气净化系统，令人关注在COVID-19大流行时期在这些地方进行开放活动的安全性。为了应对这一挑战，使用计算流体动力学，我们进行了一个系统的调查，空气传播的教室配备了一个单一的水平单元通风机（HUV）和评估性能的低成本箱风扇空气净化器的风险缓解。我们的研究表明，在教室里放置箱式风扇空气净化器可以大大降低整个空间的空气传播风险。当空气净化器放置在无症状患者附近时，可以实现最佳性能。然而，在不知道患者位置的情况下，在空气向下流动的HUV附近，清洁器的性能最佳。此外，我们发现，与单独提高HUV流速相比，通过增加空气净化器可以更有效地降低教室中的气溶胶浓度和传播。需要调整空气净化器的数量和位置，以保持其对较大教室的功效，并考虑到与寒冷季节人体热羽流和热通风空气相关的热梯度。总的来说，我们的研究表明，箱式风扇空气净化器可以作为一种有效的低成本替代方案，用于减轻通风不良空间中的空气传播风险。
Many indoor places, including aged classrooms and offices, prisons, homeless shelters, etc., are poorly ventilated but resource-limited to afford expensive ventilation upgrades or commercial air purification systems, raising concerns on the safety of opening activities in these places in the era of the COVID-19 pandemic. To address this challenge, using computational fluid dynamics, we conducted a systematic investigation of airborne transmission in a classroom equipped with a single horizontal unit ventilator (HUV) and evaluate the performance of a low-cost box fan air cleaner for risk mitigation. Our study shows that placing box fan air cleaners in the classroom results in a substantial reduction of airborne transmission risk across the entire space. The air cleaner can achieve optimal performance when placed near the asymptomatic patient. However, without knowing the location of the patient, the performance of the cleaner is optimal near the HUV with the air flowing downwards. In addition, we find that it is more efficient in reducing aerosol concentration and spread in the classroom by adding air cleaners in comparison with raising the flow rate of HUV alone. The number and placement of air cleaners need to be adjusted to maintain their efficacy for larger classrooms and to account for the thermal gradient associated with a human thermal plume and hot ventilation air during cold seasons. Overall, our study shows that box fan air cleaners can serve as an effective low-cost alternative for mitigating airborne transmission risks in poorly ventilated spaces.
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DOI：
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期刊：
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影响因子：
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发表时间：
2021-02-01
期刊：
Physics of fluids (Woodbury, N.Y. : 1994)
影响因子：
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作者：
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