To demonstrate the concept, Davidson lit a cigar inside Marlaina’s and showed how the smoke danced upward, collecting in the ceiling space with the UV fixtures.
“If somebody has undetected coronavirus and doesn’t eat with a mask and is talking and so on, the vast majority of their particles are going to get pulled up there into the killing zone and circulate and bounce around,” Davidson said. “Statistically, the risk to other people is going to be very low.”
Research shows close to 90% of airborne particles from a previous coronavirus (SARS-CoV-1) can be inactivated in about 16 seconds when exposed to the same strength of UV as in the restaurant’s ceiling. Other viruses, such as the adenovirus, are more resistant and require a higher dose of UV.
“Although it’s not perfect, it probably offers the best solution for direct air disinfection” in the current pandemic, said David Sliney, a faculty member at Johns Hopkins University and longtime researcher on germicidal UV.
When used with proper ventilation, upper-room GUV is about 80% effective against the spread of airborne tuberculosis, according to several studies. This is equivalent to replacing the air in a room up to 24 times an hour.
So, even if there is upper-room UV in a building, Corsi said, face masks and social distancing are still necessary to block larger respiratory droplets and remove some of the aerosols in the near field. But Corsi said there’s now enough evidence to show that coronavirus aerosols can hang in the air and spread throughout a room (“the far field”), and it’s time to take that airborne spread seriously.
Source: Scientists Want To Know More About Using UV Light to Fight COVID-19 Spread – Note
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