A Drexel Engineering team has turned advanced computer models of UV air disinfection into practical guidance for schools, offices and clinics. Published in Building and Environment, the study shows how to plan whole-room systems that inactivate airborne pathogens while people are present, translating complex physics into design-ready decisions.
The study centers around far-UVC, a type of ultraviolet light with germicidal properties that is often used in ceiling-mounted fixtures to disinfect air and surfaces in occupied spaces. In technical terms, the team focused on a narrow band centered at 222 nanometers that can disable viruses and bacteria in the air but does not penetrate living tissue deeply, which makes it a candidate for use while rooms are occupied.
Using computational fluid dynamics, the researchers ran 575 virtual room experiments that varied room size, air flow, fixture layout, lamp power and how susceptible different pathogens are to this light. They then distilled the results into quick-running models that estimate how much “clean air” a UV system adds, expressed as equivalent air changes per hour, or eACH.
“We built a set of virtual rooms and asked a practical question: given the fixtures you can buy and the space you have, how much extra clean-air effect will you get,” said lead author Bryan E. Cummings, PhD, a former postdoctoral researcher. “The outcome is a simple equation for early estimates and a machine learning model when you need more precision. Both remove the need to run thousands of detailed simulations.”
One practical takeaway stands out for designers. The simulations show that, all else equal, using more low-power fixtures across a room outperforms using only a few high-power fixtures. Spreading out the light increases the chance that tiny aerosols pass through irradiated regions.
The study balances performance with safety and operations. The authors note that far-UVC systems can create small amounts of ozone and other chemical byproducts indoors, which should be managed with adequate ventilation and thoughtful placement. They frame deployment as a risk-management decision that considers infection risk, community vulnerability, chemistry and energy use alongside other controls.
