Transparent air filter for high-efficiency PM2.5 capture

TLDR

Particulate matter pollution poses serious public health risks, and indoor air quality is typically maintained by costly, energy‑intensive filtration systems. This study presents a transparent air filter that protects indoor air through windows by harnessing natural passive ventilation. By tailoring surface chemistry for strong PM adhesion and designing a microstructured filter, the device achieves high transparency (~90%) while removing over 95 % of PM2.5 under extreme conditions. Field testing in Beijing demonstrated that the polyacrylonitrile filter removed 98.69 % of PM2.5 while maintaining ~77 % transmittance during haze events.

Abstract

Particulate matter (PM) pollution has raised serious concerns for public health. Although outdoor individual protection could be achieved by facial masks, indoor air usually relies on expensive and energy-intensive air-filtering devices. Here, we introduce a transparent air filter for indoor air protection through windows that uses natural passive ventilation to effectively protect the indoor air quality. By controlling the surface chemistry to enable strong PM adhesion and also the microstructure of the air filters to increase the capture possibilities, we achieve transparent, high air flow and highly effective air filters of ~90% transparency with >95.00% removal of PM2.5 under extreme hazardous air-quality conditions (PM2.5 mass concentration >250 μg m(-3)). A field test in Beijing shows that the polyacrylonitrile transparent air filter has the best PM2.5 removal efficiency of 98.69% at high transmittance of ~77% during haze occurrence.