title: Effectiveness of a personalized ventilation system in reducing personal exposure against directly released simulated cough droplets.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: School of Public Health, Maryland Institute for Applied Environmental Health, University of Maryland at College Park, College Park, MD, USA.
authors.forename: J
authors.initials: J
authors.lastname: Pantelic
authors.affiliation: Department of Building, School of Design and Environment, National University of Singapore, Singapore, Singapore.
authors.forename: K W
authors.initials: KW
authors.lastname: Tham
authors.affiliation: Department of Building, School of Design and Environment, National University of Singapore, Singapore, Singapore.|Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Copenhagen, Denmark.
authors.forename: D
authors.initials: D
authors.lastname: Licina
mesh_terms: D000336:Aerosols; D000392:Air Movements; D016902:Air Pollution, Indoor; D003198:Computer Simulation; D003371:Cough; D006801:Humans; D008348:Manikins; D014691:Ventilation
chemical_list: D000336:Aerosols
keywords: Cough; Desktop personalized ventilation; Exposure fraction; Mixing ventilation; Thermal manikin