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Characterizing the Dynamic Interactions and Exposure Implications of a Particle-Laden Cough Jet with Different Room Airflow Regimes Produced by Low and High Momentum Jets

Category: Air Pollution and Health Effects

Volume: 15 | Issue: 5 | Pages: 1955-1966
DOI: 10.4209/aaqr.2015.03.0146
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Guangyu Cao 1, Shichao Liu2, Brandon E. Boor2, Atila Novoselac2

  • 1 Department of Energy and Process Engineering, Norwegian University of Science and Technology, Kolbjørn Hejes vei 1b, 7491 Trondheim, Trondheim, Norway
  • 2 Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 1 University Station C1752, Austin, TX 78712-1076, Texas, USA

Highlights

Downward plane jets may prevent the transport of cough particles from the source.

The interaction of a cough jet and a downward plane jet could be quantified. 

Downward plane jets may reduce inter-personal exposure to coughed particles.

The results may be used in the process of diffuser selection for public buildings.


Abstract

The objective of this study is to examine the dynamic interaction of a cough jet with different indoor airflow distributions created by linear slot diffusers considering the inter-personal transport of coughed particles. The experimental measurements were performed in a chamber, where the interaction of a cough jet and downward jets with various momentums was visualized by smoke. In this study, parameters related to the dynamic interaction of a transient cough jet and a steady downward jet have been studied: (1) distance between the cough jet source and an exposed dummy (ED); (2) the initial momentum of the downward plane jet. The experimental results indicate that the ceiling-attached horizontal jets that are widely applied in the over-head mixing ventilation systems have difficulties in deflecting the cough jet, and thereby have difficulties in reducing inter-personal transport of the coughed particles. This study found that a downward plane jet could prevent the transport of cough particles from the cough dummy to the ED. When the ED is standing 0.5 meter away from the cough dummy, the personal exposure (PE) level to coughed particles by using a downward plane jet could be two orders of magnitude lower than by using ceiling-attached horizontal jets. In addition, this study quantifies the interaction of a cough jet and a downward plane jet in their ability to reduce exposure to coughed particles. The results may be used in the process of diffuser selection and suggests that ventilation systems employing downward plane jets with high discharge velocities might be useful in public spaces to reduce inter-personal exposure to coughed particles

Keywords

Downward plane jet Jet Momentum Coughed particles Human exposure


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