Researchers from Syracuse University established a three-step plan to create safe schools and office buildings that limit the spread of COVID-19 while maintaining indoor air quality (IAQ) levels. The steps include source control, ventilation and air cleaning. By implementing these steps, schools and office buildings can prevent as much of the COVID spread as possible.

The first and most important step is source control. The easiest way to stop the spread of COVID-19 is to stop the source. With source control, building managers should detect, track and isolate infected people. They should also take steps to prevent transmission through asymptomatic carriers. Asymptomatic carriers are the hardest to control, so the team says that universal face mask use and hand sanitizing before entering a space is essential.

The second step is ventilation. Building managers should focus on supplying clean outdoor air to all rooms to dilute the concentration of COVID-19 droplets. The average classroom or office building has about 20% of its air supplied from the outside. This saves on heating and cooling while meeting IAQ levels. Buildings should increase the outdoor ventilation rate to max capacity of the ventilation system. Any recirculated air should be filtered with HEPA or MERV14 filters. Proper air distribution is essential to make sure clean air reaches all people in a given area.

The team also recommended air supply to be brought in through ground ventilation. Filtered air from the ceiling can mix with the exhausted breath from potential COVID-19 carriers. With ground ventilation and displacement ventilation, air is filtered in from the floor level avoids this issue.

The third and final step is air cleaning. Buildings should be applying air filtration and purification in a building, room or a personal level. In all three scenarios, high-efficiency filters need to be in place, sufficient airflow must be supplied and the spread of droplets must be low. At the personal level, everyone in a building should wear a mask to prevent droplets. At the building level, HEPA filters should be in place in recirculated and mixed air ducts to reduce cross-contamination and increase total clean air delivery. In standalone rooms, air cleaners with HEPA filters should be implemented to further reduce the concentration of COVID-19 in a space. For rooms with insufficient airflow rate can implement air cleaners, which can double the clean air supply in a room for 25 people.

A paper on these strategies was published in Science and Technology for the Built Environment.