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Harvest of innovations at Geneva's Invention Expo
Prof. Wallace Leung (second from right) and his research team 

Prof. Wallace Leung (second from right) and his research team

Special Award and Gold Medal Multilayer nanofibre filter-nanoaerosols capture and added functions

Principal Investigator: Prof. Wallace Leung, Department of Mechanical Engineering

Multilayer nanofibre filters can be used as masks and filtering systems  

Multilayer nanofibre filters can be used as masks and filtering systems

PolyU has developed a multilayer nanofibre filter made of a light and breathable material that can effectively capture harmful air pollutants and kill bacteria. Conventional microfibre masks, even those intended for surgical use, can only effectively filter particulate matter such as PM2.5, commonly known air pollutants and only 30% of nanoaerosols that lead to even greater health threats. Composed of multiple thin nanofibre layers, this multilayer nanofibre filter performs much better by capturing 80% of aerosols with tiny particle sizes of less than 300 nanometres. Such air pollutants include diesel particulates, laser printer particles, viruses and small bacteria that easily and invisibly enter our respiratory, vascular, lymphatic and nervous systems, leading to various chronic diseases.

With a lower pressure drop than filters packed in a single layer, this filter's multiple nanofibre layers are each supported by permeable scrim materials that greatly improve breathability. Passing through the functioning nanofibre layers, gaseous pollutants can be converted to harmless substances with light exposure and bacteria can be killed through exposure to water vapour, including sweat. These air-regeneration and multiple-use functions cannot be achieved with conventional coarse microfibre filters.

This high-performing multilayer nanofibre filter can also be applied broadly in filters installed in public transportation and air ventilation systems in indoor areas.