Along with vaccines, masks and testing, indoor air hygiene and building engineering controls will be key to slowing the spread of airborne, highly infectious variants of COVID-19, according to researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory. They presented a review of the state of the science for several key strategies to reduce airborne infection risk using building controls, including ventilation, filtration, airflow management and disinfection by germicidal ultraviolet (UV) light.
“We found strong evidence that indoor environmental controls can be effective against transmission,” says Rengie Chan, a Berkely researcher. “Implementing building controls effectively and at scale while considering operational challenges and energy costs are critically important to support in-person activities in our schools, offices, and other types of indoor spaces where people gather,”
Chan and colleagues used a computer simulation to demonstrate the way various building control adjustments affected transmission risk at the nearby, room-scale and building-scale levels. Respiratory aerosols, which can carry viruses, mix throughout a room in minutes, but they can be substantially removed from the room by ventilation or filtering the air within the room, reducing exposure. In addition to engineering controls, maintaining even 2-3 feet of personal space substantially reduces the potential for direct transfers from one person to another.
Effective building controls can take many forms. Ventilation can be achieved by opening windows and increasing outdoor airflow through an HVAC system. Filtration can involve upgrading HVAC filters to a higher efficiency rating or using standalone or portable air cleaners. Cost-effective, whole-room disinfection is possible through the use of germicidal UV light, which is underutilized but has previously been effective in interrupting the spread of measles during school outbreaks.
Dan Hounsell is senior editor of the facilities market. He has more than 25 years of experience writing about facilities maintenance, engineering and management.
