Researchers from the University of California, Riverside, and George Washington University have created a polymer nanothread-based filter that can capture 99.9% of coronavirus aerosols.

Since the start of the pandemic, there have been many measures put in place to curb aerosol spread of COVID-19, including improving indoor ventilation via air filtration systems and mask mandates. The team set out to create a fiber that could be used in masks and filtration systems to remove as much of the dangerous aerosol as possible.Left: A nanofiber filter that captures 99.9% of coronavirus aerosols; Right: A highly magnified image of the polymer nanofibers. Source: Yun ShenLeft: A nanofiber filter that captures 99.9% of coronavirus aerosols; Right: A highly magnified image of the polymer nanofibers. Source: Yun Shen

The new filter is produced by sending high electrical voltage through a drop of liquid polyvinylidene fluoride to spin the threads. This creates pores that are only a couple of micrometers wide on nanofiber surfaces. The electrospinning production method is cost-effective and could be used to mass-produce nanofiber filters for PPE and air filtration systems. It creates nanofibers with an electrostatic charge that enhances the ability to capture aerosols. The high porosity makes it easy for the users to breathe while wearing a mask made with the filter.

The effectiveness of the filter was tested with an aerosol saline solution and an aerosol that contained a coronavirus that only affects mice and is in the same family as aerosols that cause COVID-19. The team compared the effectiveness of surgical masks, cotton masks, neck gaiter and their electrospun nanofiber filter. The cotton mask and neck gaiter removed 43% to 73% of aerosols, the surgical mask removed about 98% of aerosols and the nanofiber removed almost all of the aerosols.

A paper on the new filter was published in Environmental Science and Tech Letters.