Scientists have found that dangerous airborne viruses can be rendered harmless on-the-fly when exposed to ‘cold plasma’ – a stream of energetic, charged fragments of air molecules. The team from University of Michigan in the US hope to one day harness this capability to replace the surgical mask. The researchers have measured the virus-killing speed and effectiveness of non thermal plasmas – the ionised, or charged, particles that form around electrical discharges such as sparks.
A non thermal plasma reactor was able to inactivate or remove from the air stream 99.9 per cent of a test virus. To gauge non thermal plasmas’ effectiveness, researchers pumped a model virus — harmless to humans — into flowing air as it entered a reactor. Inside the reactor, borosilicate glass beads are packed into a cylindrical shape, or bed. The viruses in the air flow through the spaces between the beads, and that is where they are inactivated.
The researchers were able to determine that more than 99 per cent of the air sterilising effect was due to inactivating the virus that was present, with the remainder of the effect due to filtering the virus from the air stream. Achieving these results in a fraction of a second within a stream of air holds promise for many applications where sterile air supplies are needed.