Airflow deflectors of external windowsto induce ventilation: Towards COVID-19 prevention and control

Ventilation strategies to reduce airborne transmission of viruses in classrooms: A systematic review of scientific literature

“…In this regard, in Ref. [ 95 ] different settings of airflow deflectors applied on external windows were analysed in a classroom. Combining CFD simulations and the Wells-Riley equation, the authors report that by installing 90-degree deflectors on the external windows the infection probability decreases by 19.3% (from 41% to 21.8%) when the source is located in the middle of the class not in line with the window, while installing 45-degree deflectors reduces the infection probability by 17.5% (from 57.5% to 40%) when the source is located in line with the window.…”

“…To summarise, it can be deduced from these studies that under conditions of air changes greater than 6.5 ACH the risk of contagion can be less than P = 1% if face masks are worn, while without face masks, at least 22 ACH are required to set the contagion risk under 1% [ 70 , 94 ]. If unable to have these air changes, the strategy to reduce the risk of contagion may be to install low-cost fans that can reduce the risk of contagion by up to 70% [ 94 ], or deflectors that can give up to 20% risk reduction [ 95 ]. As demonstrated from the other reported studies, air monitoring sensors or control units based on the infection risk can be used to manage windows opening procedures to mitigate new infection cases [ 71 , 72 , 76 ].…”

“… ref. Method Room volume N. students Aeration strategy Evaluation parameter [ 70 ] MM 168 m 3 (8.20 × 7.90 × 2.60) NA Single-sided ventilation and cross-ventilation with different windows opening ratio Probability of infection [ 94 ] NM/MM 595 m 3 (14.00 × 8.50 × 5.00) 40 Cross-ventilation with different windows opening and integrated fan Probability of infection/Particles concentration [ 81 ] NM 216 m 3 (12.00 × 6.00 × 3.50) 10 Different positions and heights of the windows Particles concentration [ 95 ] NM 595 m 3 (14.00 × 8.50 × 5.00) NA Cross-ventilation with different window airflow deflectors Probability of infection [ 71 ] MM 11 classrooms 112–155 m 3 5–21 CO2-based aeration CO2 concentration [ 72 ] MM 150 m 3 NA Risk infection-based aeration Probability of infection [ 76 ] MM 150 m 3 (50 m 2 × 3 m) NA Risk infection-based aeration …”

Effect of resilient architecture in an ancient windmill in the Sistan region on natural ventilation enhancement

“…Wing walls or deflectors 27 are vertical 28 or horizontal 29 solid elements around and near windows or windcatchers 30 , enhancing natural single-side ventilation 31 , 32 by creating extra pressure gradients among openings. It can induce natural suction ventilation by producing a low-pressure region on outlet windows 33 .…”

Natural Ventilation and Aerosol Particles Dispersion Indoors

“…Chen et al [22] put forward recommendations for ventilation of indoor spaces to reduce COVID-19 transmission. Che et al [23] proposed airflow deflectors of external windows to induce ventilation, thus providing some means of COVID-19 prevention and control. Ding et al [12] studied the contagion events in enclosed spaces and the engineering control of contaminant aerosol particles spread using ventilation systems in health care facilities and public vehicles.…”