The Hawai‘i Department of Education will be distributing box fans and carbon dioxide sensors to all schools statewide for use in rooms without air conditioning. The demonstrations, using the "5-Step Guide to Measuring Ventilation in Classrooms,"¹ illustrate the effectiveness of opening windows and/or doors in combination with box fans. By simply opening a door and adding a box exhaust fan, ventilation (providing clean outside air to a room or building) was improved from almost no air exchange to over 9 air exchanges per hour (ACH). Opening a window further enhanced this effect, resulting in 20 ACH.

The box fans and carbon dioxide sensors being provided to schools will enable school staff to enhance ventilation and measure the effectiveness of their effort. Adjustments can be made to occupancy, outside air supply, and use of portable HEPA air cleaners in order to provide an optimal risk reduction school environment.

The Lasko box fan screen holes are approximately 1 inch wide by 0.5 inch tall and the fan blade is recessed approximately 1.5 inches. Fans should be placed out of reach of small children (e.g. at window level) to discourage the insertion of objects such as pencils or fingers into the fan.

Background:

SARS-CoV-2 (COVID-19) infection has increasingly been recognized to be associated with aerosol transmission of fine airborne particles produced by breathing, talking, shouting, singing, coughing and other normal activities². Evidence for this transmission mechanism includes infection by asymptomatic and pre-symptomatic individuals and "superspreader" events. Therefore, wearing high quality face masks and enhancing ventilation are key steps in mitigating exposure risk.

According to the Centers for Disease Control, ventilation is one component of maintaining healthy environments, and is an important COVID-19 prevention strategy for schools and childcare programs.

Ventilation can be enhanced by:

• Increasing percentage of outside air via air conditioning systems.

• Increasing filtration efficiency of air conditioning systems or by adding portable HEPA air cleaners.

• Opening windows and/or doors in non-air conditioned spaces and using fans to increase the effectiveness of open windows.

This website presents information on enhancing ventilation that we will test using methods designed and made available by the Harvard TH Chan School of Public Health.

¹ Allen J., Spengler J, Jones E, Cedeno-Laurent J "5-Step Guide to Checking Ventilation Rates in Classrooms" Harvard Healthy Buildings Program.

² Greenhalgh T, Jimenez JL, Prather KA, Tufekci Z, Fisman D, Schooley R. "Ten scientific reasons in support of airborne transmission of SARS-CoV-2" Lancet. 2021 Apr 15:S0140-6736(21)00869-2. doi: 10.1016/S0140-6736(21)00869-2. Epub ahead of print. PMID: 33865497; PMCID: PMC8049599.