A practical approach for preventing dispersion of infection disease in naturally ventilated room

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

“…In [ 94 ], the impact of windows design on airflow distribution and infection probability was investigated using CFD simulation and Wells-Riley equation in a naturally ventilated classroom with cross ventilation. Although various configurations of window opening are simulated with 1.6 ACH, contagion risks remain between 35% and 70%.…”

“…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 …”

“…In the second case though, too low VRs can be reached, which entail too high risks of contagion. In this type of classroom, NVS alone is not sufficient to ensure a low risk, and other strategies should be considered, such as, installing APs, or integrating low-cost fans into the windows to always guarantee an adequate exchange of air when difference in temperature and pressure between inside and outside do not allow it [ 94 ].…”

Ventilation Strategies for Mitigation of Infection Disease Transmission in an Indoor Environment: A Case Study in Office

“…The reasonable usage of natural ventilation and mechanical ventilation is suggested during the normalization phase of COVID-19, such as in offices and classrooms [23][24][25]. Natural ventilation possesses the advantage of energy efficiency, through bringing outdoor air to an indoor room based on thermal pressure or wind pressure [26].…”