Researchers at the University of California, Riverside, have developed a nanofiber filter that is very effective at removing coronavirus aerosols from the air. As the main source of COVID-19 transmission, aerosols pose a continuing threat. Technologies are being developed to remove aerosols from the air in buildings or as personal protective equipment for the long-term fight against COVID-19. The latter material contains tiny pores, only a few micrometers in size, and is highly effective at capturing aerosols.
Aerosols are small stains of water and other materials that are suspended in the air after people talk, cough, or snore. During the current pandemic, they are an important source of COVID-19 transmission, as viral particles can trap an infected person to a new victim by attaching to an aerosolized droplet. Wearing a conventional mask helps reduce the dispersion of aerosols, but does not nearly eliminate the risk.
Aerosols are the focus of the ongoing discussion on masks, ventilation, and air filtration as methods to reduce viral transmission. For air filters and masks, the key component is the material used to filter the aerosols, as they are surprisingly difficult to capture. This new study used coronavirus aerosols to compare various face masks and air filters in their ability to stop aerosols on their tracks.
“Our work is the first study to use coronavirus aerosols to evaluate the filtration efficiency of facial masks and air filters,” said Yun Shen, a researcher involved in the study. “Previous studies have used substitutes for saline solutions, polystyrene beads and bacteriophages, a group of viruses that infect bacteria.”
Researchers have developed a new filter made from electrospun fibers that are approximately 167 times thinner than human hair. The fiber network includes small pores only a couple of micrometers in diameter. Electrospinning imparts an electrical charge to the fibers, which can increase their ability to capture aerosols. Although, even though the pores are small, the material is very porous, which should make breathing easier.
To test the new material, the team compared it to surgical and cotton masks and a leggings for the neck in terms of ability to capture coronavirus-laden aerosols. The coronavirus in question was one that can infect mice, but is harmless to humans. The copper mask and cotton mask removed between 45% and 73% of the aerosols and the surgical mask up to 98%, but none worked as well as the new electrospun material, which removed 99.9%. .
“Electrospinning can advance the design and manufacture of face masks and air filters,” Shen said. “The development of new masks and air filters through electrospinning is promising for its high filtration performance, economic viability and scalability, and can meet the on-site needs of air masks and filters.”
Study the magazine Environmental science and technology charts: Development of Electrospun nanofibrous filters for the control of coronavirus aerosols