Nose-Inspired Filtration: A New Path for Clean Indoor Air
Air pollution inside buildings is often invisible, yet it shapes the quality of every breath. Tiny particles such as dust, pollen, and soot flow through conventional filters, only to be dislodged by strong or shifting airflow. Now, researchers led by Associate Professor Sanghyuk Wooh at Chung-Ang University have unveiled a breakthrough: a reusable air filter that mimics the human nose and uses a thin oil coating to trap particles with far greater effectiveness.
How Conventional Filters Fall Short
Traditional filters primarily rely on physical sieving and van der Waals forces to capture particles. While this approach works for larger debris, it struggles with ultrafine particles and high-velocity air. The captured matter can be shaken loose when air moves unpredictably, leading to recontamination and higher energy demands as fans push air through tighter media. The result is a filter that not only becomes less efficient over time but also increases wear on HVAC systems.
The Oil-Coated Innovation: Bringing the Nose to Filtration
The PRO (particle-removing oil-coated) filter is engineered by applying a very thin, stable oil film onto polymer-coated fibers. The inspiration comes from mucus-coated nasal hairs, which trap particles effectively without obstructing airflow. The team sprayed a carefully chosen oil onto polymer brushes, ensuring even distribution and strong adhesion. Importantly, the oil coating does not clog the pores; air can pass freely, but particles become trapped in the oil layer.
Where van der Waals forces offer only weak attractions, capillary forces generated by the oil create a much stronger grip. This surface tension pulls particles toward the fibers and holds them in place, delivering forces in the micronewton to sub-micronewton range—thousands of times stronger than traditional mechanisms. The result is a filtration system that maintains high airflow while improving particle retention.
Real-World Benefits: Efficiency, Reusability, and Energy Savings
Lab tests show the PRO filter exceeds conventional filters across a spectrum of particle sizes—from pollen to ultrafine dust—by 10–30% in filtration efficiency, without sacrificing airflow. The most striking advantage: superior performance under strong or changing airflow. Filters that typically shed captured dust during gusts or direction shifts now retain it due to the oil layer’s grip. This feature is particularly valuable in places with variable ventilation, such as subways, industrial sites, and outdoor dining areas.
Dr. Wooh notes that this approach implies a zero-energy filtration concept when leveraging natural wind, and it can even work without a powered fan in some open-space configurations. The PRO filter’s design opens the door to ventilating public areas more sustainably and quietly, reducing reliance on energy-intensive fans.
Costs, Reusability, and Environmental Impact
Another major advantage is reusability. When the oil becomes dirty or saturated, it can be washed away, and a fresh oil layer restores performance. Field trials in real HVAC systems showed the PRO filter lasting about twice as long as standard filters while capturing more dust and cutting energy use by roughly 20%. This combination lowers maintenance needs, reduces plastic waste from disposables, and enhances overall system efficiency.
Looking Ahead: A Smarter, Greener Future for Filtration
The PRO filter demonstrates that the next generation of air purification can emerge from simple, nature-inspired chemistry and design. By pairing oil chemistry with compatible polymer brushes and maintaining an ultra-thin coating, researchers achieve strong particle capture without clogging pores. Future iterations may tailor oil coatings to specific environments or automate oil refresh cycles, offering tailored, sustainable solutions—from classrooms to hospitals to factories. The underlying principle remains clear: drawing on biological strategies can yield robust, low-energy air filtration for a healthier planet.
Research findings are available online in the journal Nature.
