Non-thermal (or cold) plasma has been around for years. A version of this technology is incorporated into power plants to stop particles being released into the atmosphere. It can also be used to decontaminate food.
Now, researchers have developed an exciting new use for the stuff – the eradication of potentially dangerous viruses floating in the air.
Indeed, cold plasma is so good at its job, it can kill 99.9 percent of airborne viruses, researchers at the University of Michigan found. Their research is published in the Journal of Physics D: Applied Physics.
Some viruses (say, measles) can survive in the air for several kilometers. It is part of what makes them so contagious. But it is also what makes them so hard to defend against.
"The most difficult disease transmission route to guard against is airborne because we have relatively little to protect us when we breathe," Herek Clack, University of Michigan research associate professor of civil and environmental engineering, said in a statement.
His team hopes to change that. The new technology utilizes cold plasmas, the ionized particles that form around electrical discharges. The reactor they built, designed for buildings, contained borosilicate glass beads, which were packed into a cylindrical shape. The air passes through the reactor and the spaces between the beads, where the virus is inactivated.
"In those void spaces, you're initiating sparks," Clack said. "By passing through the packed bed, pathogens in the air stream are oxidized by unstable atoms called radicals. What's left is a virus that has diminished ability to infect cells."
"The results tell us that nonthermal plasma treatment is very effective at inactivating airborne viruses," Krista Wigginton, assistant professor of civil and environmental engineering, said in a statement. Indeed, it was able to inactivate or remove 99.9 percent of a test virus, achieving results in a fraction of a second.
"There are limited technologies for air disinfection, so this is an important finding," Wigginton said.
It has the potential to work "better, faster, and more cheaply" than conventional filters, added Clack.
Right now, the researchers are taking their work to pig farms. The pig farm in question knows it has infected animals so Clack and his team plan to test the efficacy of their device on the air exhausted from its buildings. In the future, they hope variations of this technology can be used as a (more effective) replacement for surgical masks.
The next stage, Clack says, will be "human applications". That will involve miniaturizing the technology currently adapted for buildings so that it becomes a device you can wear.
The end result – one day, not too far away, we might all be carrying our own bug-killing machines.
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