A group of researchers, including those at the University of Houston, has developed an air filter that can instantly kill SARS-CoV-2 viral particles that pass through it by heating them to 200 degrees C (392 F). The technology may help to destroy the particles within busy indoor spaces, such as hospitals, reducing the risk of COVID-19 transmission.
There is increasing evidence that SARS-CoV-2 viral particles could linger in the air for several hours when indoors, posing an infection risk for much longer than once thought. Previously, health authorities advised that the primary sources of COVID-19 infection are droplets expelled by people sneezing and coughing, that rapidly fall to the ground soon after.
However, much smaller aerosolized particles may linger in the air for quite some time, especially in poorly ventilated indoor spaces, suggesting that we may need new strategies to protect ourselves from airborne infection. One such approach involves filtering the air in indoor spaces to remove or destroy airborne particles, and this group of researchers has created such a filter.
“This filter could be useful in airports and in airplanes, in office buildings, schools and cruise ships to stop the spread of COVID-19,” said Zhifeng Ren, a researcher involved in the study. “Its ability to help control the spread of the virus could be very useful for society.”
The filter contains a porous and flexible nickel foam, which is electrically conductive, meaning that it can be heated. To achieve the high temperatures needed to kill the viral particles nearly instantly, the researchers folded the foam to increase its resistance, thereby increasing the heat produced.
As the filter is internally heated, relatively little heat escapes from it into the room, meaning that it doesn’t place an undue strain on air conditioning systems. In tests, the system killed 99.8% of SARS-CoV-2 viral particles in a single pass, suggesting that it could significantly reduce particle levels in enclosed spaces.
“This novel biodefense indoor air protection technology offers the first-in-line prevention against environmentally mediated transmission of airborne SARS-CoV-2 and will be on the forefront of technologies available to combat the current pandemic and any future airborne biothreats in indoor environments,” said Faisal Cheema, another researcher involved in the study.
Study in Materials Today Physics: Catching and killing of airborne SARS-CoV-2 to control spread of COVID-19 by a heated air disinfection system