Researchers are exploring a new way to create personalized ventilation systems that would remove airborne pathogens to help reduce the spread of respiratory diseases in enclosed spaces. (Credit: UBCO)
Airborne germs are neutralized quickly after exhalation, lowering infection risk by over 80%.
In A Nutshell
- Canadian researchers designed an air-cleaning device that captured about 94% of exhaled germ-sized particles in computer simulations of two people meeting face-to-face for 30 minutes
- The system works by redirecting airflow between people rather than blowing air directly at faces, and it maintained effectiveness even when people shifted position by about 4 inches
- Simulations estimated the device reduced modeled infection risk to 9.5%, compared with over 91% for standard room ventilation alone, though these are theoretical calculations based on particle counts, not real-world infections
Canadian researchers have designed an air-cleaning system that intercepts germ-sized particles right where people breathe them out. In computer simulations of two people meeting face-to-face, the device removed about 94% of exhaled aerosols before they could spread through the room.
The system, developed at the University of British Columbia, solves a longstanding problem with air purifiers; most can’t capture contaminated air fast enough before it mixes throughout a space. The simulations estimated that over 30 minutes, a person near the device had just a 9.5% chance of infection, compared with more than 91% with regular room ventilation alone.
Rather than blowing a jet of air directly at someone’s face, which many find uncomfortable, the device quietly redirects airflow between people. It’s designed to avoid the eye and skin dryness that makes traditional personal ventilation systems unpopular, though researchers didn’t directly measure comfort in this study.
Capturing Particles Where People Breathe
The device works with two parts positioned between people having a conversation. A narrow rectangular opening releases clean air at carefully calculated angles. A larger intake panel on the other side pulls contaminated air toward a purification unit. As the clean air flows out, it creates a current that sweeps up aerosol-laden breath before those particles can float away.
Published in Building and Environment, the study tested different arrangements to find what worked best. The sweet spot was positioning the device within about 2 inches horizontally from where someone breathes. Even when placed farther away, the system still removed between 60% and 80% of particles, depending on the setup.
Getting the air speeds right mattered. The device releases clean air at a rate more than three times slower than it pulls contaminated air in. When researchers tried higher release speeds, the outgoing air hit the intake area and allowed germs to escape back into the room. Lower speeds didn’t create enough flow to overcome the natural rising of warm air from people’s bodies.
How It Stacks Up Against Existing Systems
Researchers modeled a realistic meeting scenario with two people sitting across from each other for half an hour. One person acted as if infected, releasing 300 tiny particles every second at a size of one micrometer, small enough to float in air for long periods.
During those 30 minutes, the infected person breathed out 540,000 particles total. With the new device running in the best position, only 10 particles reached the other person’s lungs. Regular room ventilation let 247 particles reach the other person. A conventional personal ventilation jet, which blows clean air at someone’s face, let 65 particles through.
Scientists also tested a combined approach using both ventilation jets and exhaust vents near each person. That setup reduced modeled infection risk to 38%, better than room ventilation alone but nowhere near as effective as the new device.
Traditional personal ventilation has been around for more than 30 years. These systems typically shoot air at about 8 miles per hour toward someone’s face. That constant breeze dries out eyes and skin, prompting many people to switch them off. Research has also found these systems can actually spread more germs if only the sick person uses one, making things worse for everyone nearby.
What Happens When People Move
A key test came when researchers simulated people shifting in their seats. When someone moved about 4 inches to the side, a natural fidget during any meeting, the new device still worked well. Only 69 particles reached the other person. Traditional ventilation systems completely failed when people weren’t perfectly aligned. In that scenario, 872 particles got through, and the modeled infection risk shot up to nearly 100%.
After just 15 minutes with people slightly out of position, conventional ventilation created worse conditions than having no special system at all. The misaligned traditional ventilation jet produced a nearly certain infection risk in the model. The new system, even when offset, still performed about as well as a perfectly positioned traditional jet, with infection probability around 50%.
This flexibility matters because people don’t sit perfectly still during real conversations. Any ventilation system that only works when everyone stays frozen in place has limited practical use.
Temperature and Other Real-World Factors
The device maintained about 94% removal efficiency when room temperature ranged from 16.5°C to 26°C (roughly 62°F to 79°F). Performance dipped slightly to 86% at 30°C (86°F), probably because the smaller temperature difference between human bodies and surrounding air created weaker rising air currents that normally help collect particles.
The computer model included factors like heat rising from bodies at a rate equivalent to a 70-watt light bulb per person, breathing patterns that alternated between the two people, and a heating and cooling system exchanging room air twice per hour. The simulated room measured about 16 feet long, 11 feet wide, and 8 feet high, with people sitting less than 3 feet apart.
Current options for cleaning air near people have drawbacks. Regular air purifiers need to be positioned uncomfortably close to work well, which isn’t practical outside hospitals or dental offices. Even high-powered evacuators used by dentists only capture about 60% of aerosols, and they require positioning that would feel intrusive in an office or classroom.
The new system works with the natural upward flow of warm air from bodies instead of fighting it. The device essentially herds contaminated air toward its cleaning system before particles can spread throughout the room.
Tracking particles revealed clear differences between systems. With only standard ventilation, floating particle levels stayed highest throughout the test. The new device kept airborne particle concentrations lowest. Deposition patterns varied too. Traditional ventilation caused about 36% of released particles to land on surfaces, with more than half of those landing on the sick person’s face.
Scientists validated their computer simulations by comparing them to real experiments in a controlled chamber. The model matched actual measurements of how particle concentrations decreased over time, confirming the approach was accurate. The infection estimates are educated guesses based on how many particles reached someone, not actual case counts. The model assumed 100 viral particles would likely cause infection, with each particle adding a 1% risk.
The device’s ability to keep working well even when people move around naturally makes it more practical for real-world use in offices, medical consultation rooms, and other shared spaces where airborne disease remains a concern.
Disclaimer: This article discusses computer simulations of an experimental device that has not been tested in real-world settings or evaluated for safety and efficacy by regulatory agencies. The infection risk percentages mentioned are theoretical estimates from computational models, not measured health outcomes. This information is for educational purposes only and should not be considered medical advice. Consult qualified healthcare professionals for guidance on disease prevention and indoor air quality concerns.
Paper Summary
Limitations
The study modeled normal breathing and didn’t include coughing or sneezing, which create different airflow patterns and vary depending on whether people cover their mouths. The simulations treated each particle as containing one pathogen, a simplification. Real particles might carry multiple viruses, one virus, or none at all. Determining actual viral loads requires biological data beyond this engineering study. Researchers didn’t measure thermal comfort with standard metrics, though they designed the device to address problems reported with conventional systems. The model assumed heating and cooling systems supplied clean air without accounting for outdoor pollution. The system is meant to work alongside existing ventilation, not replace it.
Funding and Disclosures
The researchers used computing resources from the Digital Research Alliance of Canada for their simulations. The paper disclosed no specific funding sources or conflicts of interest.
Publication Details
Zabihi, M., Li, R., & Brinkerhoff, J. “A novel aerosol induction-removal system for mitigating airborne disease transmission in shared indoor environments,” was published online in Building and Environment, December 1, 2025, Vol. 286, 113569. DOI: 10.1016/j.buildenv.2025.113569. Authors are from the School of Engineering, Faculty of Applied Science, University of British Columbia, Kelowna, Canada.
