High-Efficiency allergenic pollen filtration with reusable PTFE membranes

Allergenic pollen triggers atopic reactions in pollen-allergic individuals, leading to asthma, rhinitis, dyspnea, conjunctivitis, and other symptoms. While disposable masks offer protection against such pollen, the mask production generates significant solid waste that is often not recycled, raising environmental concern. In this work, a reusable pollen-proof mask made of polytetrafluoroethylene (PTFE) membranes was developed. The PTFE membrane filtration performance against sensitized pollen was studied in comparison with medical surgical mask and N95 respirator. The regeneration performance of the filters was evaluated by evaluating pollen residue and gas permeability. Furthermore, an allergen-induced allergic rhinitis mouse model was established to assess the PTFE membrane protection efficiency. Our results revealed that PTFE-3 membrane efficiently retained pollen particles (99.999 % retention) while maintaining high gas permeance (3291 m³·m⁻²·h⁻¹·kPa⁻¹), yielding low pollen concentrations after filtration to < 5 μg·m⁻³ regardless of the pollen type, concentration, or filtration velocity. After four cycles of reuse, the residual pressure drop of the PTFE-3 membrane was only 5 Pa, and the decrease in the gas permeability was 118 m³·m⁻²·h⁻¹·kPa⁻¹, significantly outperforming the commercial masks, which underwent a greater pressure drop 11 Pa and a larger decrease in gas permeance 1175 m³·m⁻²·h⁻¹·kPa⁻¹. Significant improvement in allergic responsiveness in the nasal region of mice further confirmed the effectiveness of PTFE-3 membrane in protecting against allergic diseases. Therefore, PTFE-3 membrane masks emerge as an innovative, highly effective, and reusable alternative for commercial masks for pollen protection, providing an environmentally friendly and effective means of protecting against allergic diseases.