Sustainability in Air filtration

Multilayer Reusable Filtration Systems for Aerosol Control: From Respiratory Protection to HVAC Applications

Secours, Michelle¹; Xu, Xinyu²; Brochu, Vincent³
¹Frëtt Solutions Inc., Québec, Canada
²Department of Environnemental Engineering, Concordia University, Montréal, QC, Canada
³Department of Bioaerosols, Université Laval, Québec, QC, Canada

Keywords: aerosol filtration, reusable PPE, multilayer membranes, microplastics, sustainability.

Aerosol science plays a critical role in understanding airborne transmission of pathogens and particulate pollution. Respiratory protection devices and high-efficiency filtration systems are central tools for mitigating exposure in healthcare, industrial, and built environments. However, the global reliance on single-use polymer-based filtration products has generated significant environmental burdens, including large volumes of microplastic release and waste.

Recent advances in aerosol filtration have improved particle capture efficiency through electrostatic meltblown layers and nanofiber media. While these technologies achieve high filtration efficiencies (e.g., N95/FFP2, HEPA), their performance often degrades with humidity, decontamination, or reuse. Lifecycle analyses increasingly highlight the carbon and material footprint associated with disposable masks, respirators, and HVAC filters. Emerging research therefore calls for durable, mechanically robust filtration architectures capable of repeated reprocessing without loss of performance.

A key knowledge gap concerns the design of reusable, multilayer filtration systems that maintain high aerosol capture efficiency across size fractions while minimizing fiber shedding and microplastic generation over extended cycles. Furthermore, scalable adaptation of a single filtration architecture across multiple applications—from face masks to respirators to HVAC/HEPA systems—remains underexplored.

Here, we present a patented multilayer membrane technology (ëncore®, Canadian Patent No. 3,172,147) developed through industry–academic collaborations. The architecture combines mechanically stable microfiltration layers with durable structural supports, enabling high filtration efficiency across submicron aerosols while sustaining performance over repeated wash and sterilization cycles. Experimental aerosol testing and material characterization demonstrate stable particle filtration and limited fiber degradation after multiple reprocessing cycles. The modular multilayer concept allows adaptation to reusable surgical masks, elastomeric-style respirators, and building-scale HVAC/HEPA filters. Beyond infection control, this approach offers a pathway to substantially reduce single-use plastics and microplastic emissions in aerosol mitigation strategies, contributing to more sustainable airborne risk management systems.