Daylight passing through smart windows results in almost complete disinfection of surfaces within 24 hours while still blocking harmful ultraviolet (UV) light, according to new research. For this research, she tested four strains of hazardous bacteria — methicillin-resistance Staphylococcus aureus, Klebsiella pneumoniae, E. coli and Pseudomonas aeruginosa — using a mini-living lab set-up. The lab had smart windows, which tint dynamically based on outdoor conditions, and traditional windows with blinds.

Dr. Sepideh Pakpour is an Assistant Professor at UBC Okanagan’s School of Engineering. For this research, she tested four strains of hazardous bacteria — methicillin-resistance Staphylococcus aureus, Klebsiella pneumoniae, E. coli and Pseudomonas aeruginosa — using a mini-living lab set-up. The lab had smart windows, which tint dynamically based on outdoor conditions, and traditional windows with blinds. The researchers found that, compared to windows with blinds, the smart windows significantly reduce bacterial growth rate and their viability.

In their darkest tint state, Dr. Pakpour says smart windows blocked more than 99.9 per cent of UV light, but still let in short-wavelength, high-energy daylight which acts as a disinfectant. This shorter wavelength light effectively eliminated contamination on glass, plastic and fabric surfaces.

In contrast, traditional window blinds blocked almost all daylight, preventing surfaces from being disinfected. Blinds also collect dust and germs that get resuspended into the air whenever adjusted, with Dr. Pakpour noting previous research has shown 92 per cent of hospital curtains can get contaminated within a week of being cleaned.

«We know that daylight kills bacteria and fungi,» she says. «But the question is, are there ways to harness that benefit in buildings, while still protecting us from glare and UV radiation? Our findings demonstrate the benefits of smart windows for disinfection, and have implications for infectious disease transmission in laboratories, health-care facilities and the buildings in which we live and work.»

The pandemic has elevated concerns about how buildings might influence the health of the people inside. While particular attention has been paid to ventilation, cleaning and filtration, the importance of daylight has been ignored. According to research shared in a recent Harvard Business Review, office workers are pushing for «healthy buildings» as part of the return to work and consistently rank access to daylight and views among their most desired amenities.

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Materials provided by University of British Columbia Okanagan campus. Note: Content may be edited for style and length.