High up near the ceiling, in the dining room of his Seattle-area restaurant, Musa Firat recently installed a "killing zone" _ a place where swaths of invisible electromagnetic energy penetrate the air, ready to disarm the coronavirus and other dangerous pathogens that drift upward in tiny, airborne particles.
Firat's new system draws on a century-old technology for fending off infectious diseases: Energetic waves of ultraviolet light _ known as germicidal UV, or GUV _ are delivered in the right dose to wipe out viruses, bacteria and other microorganisms.
Research already shows that germicidal UV can effectively inactivate airborne microbes that transmit measles, tuberculosis and SARS-CoV-1, a close relative of the novel coronavirus. Now, with concern mounting that the coronavirus that causes COVID-19 may be easily transmitted through microscopic floating particles known as aerosols, some researchers and physicians hope the technology can be recruited yet again to help disinfect high-risk indoor settings.
"I thought it was a great idea, and I want my customers to be safe," said Firat whose casual eatery, Marlaina's Mediterranean Kitchen, is 20 minutes south of downtown Seattle.
As the U.S. grapples with how to interrupt the spread of the highly infectious virus, UV is being used to decontaminate surfaces on public transit and in hospitals where infectious droplets may have landed, as well as to disinfect N95 masks for reuse. But so far using this technology to provide continuous air disinfection has remained outside of most mainstream, policy-setting conversations about the coronavirus.
Experts attribute this to a combination of factors: misconceptions about UV's safety, a lack of public awareness and technical know-how, concerns about the costs of installing the technology, and a general reluctance to consider the role of aerosols in the spread of the coronavirus.
Aerosols are microdroplets expelled when someone exhales, speaks or coughs. Unlike the larger and heavier respiratory droplets that fall quickly to the ground, aerosols can linger in the air a long time and travel through indoor spaces. When someone catches a virus this way, the process is called "airborne transmission."
It's already recognized that the coronavirus can spread by means of aerosols during medical procedures, which is why health care workers are advised to wear respirators, such as N95 masks, that filter out these tiny particles. Yet there is still considerable debate over how likely the virus is to spread in other settings via aerosols.
Recently, the question of airborne transmission gained new urgency when a group of 239 scientists called on the World Health Organization to take the threat of infectious aerosols more seriously, arguing that the "lack of clear recommendations on the control measures against the airborne virus will have significant consequences."
WHO officials conceded that more research is needed but maintained that most infections do not happen this way.
As the science continues to evolve, UV could emerge as an attractive safeguard against airborne transmission _ one with a track record against pathogens _ that can be deployed to reduce the risk of infectious aerosols accumulating in indoor settings such as schools and businesses.
