A new study has indicated that the coronavirus particles cannot survive for a very long time while suspended in the air.
According to the study, coronavirus quickly loses the capacity to infect within about 10 minutes.
As reported by Insider, the laboratory study conducted by scientists at the University of Bristol, United Kingdom, however, did not include the Omicron variant of COVID-19 which experts say could behave differently.
The scientists said that their laboratory study suggested that coronavirus quickly lost its ability to infect human cells after it was released in tiny droplets suspended in the air.
According to the researchers, the study suggested that the coronavirus particles dry up in the environment outside the body, hampering their ability to infect cells.
The study, published as a pre-print on Monday that has not been independently reviewed, provides clues as to how aerosols that are released when talking and sneezing contribute to infection, Insider reported.
During the study scientists at the University of Bristol, UK designed a machine that can keep the airborne droplets in levitation.
Researchers were able to change the temperature and humidity in the chamber to mimic the conditions in the outside air. They were able to put the droplets containing the virus on human cells in a Petri dish. When the virus grows there, it’s still alive.
In the setting, the study found that within about five seconds of being released in 40 per cent humidity air which is similar to the settings in an office, or a bar half of the virus was no longer unable to infect human cells.
The ability of the virus to infect cells further dwindled over time.
Within ten minutes, the “majority” of the virus was inactivated, the authors said in the study, while within 20 minutes, about 90 per cent of the virus particles were inactive.
Humidity was more important than temperature in preserving the viruses’ ability to survive in the air, the study said.
In higher humidity, about the level seen in a shower or steam room, the virus stayed stable much longer, as pictured in green above.
Half of the particles were still able to infect within the first minutes of being suspended, the results said. But over time the particles decayed, losing most of their ability to infect within 20 minutes, like at lower humidity levels.
It is not clear how reproducible these results are to real-life settings where there are other factors at play, like ventilation, size of the room, and how much virus an infected person is shedding.
The study was conducted before the Omicron variant became widespread making it unclear if the result could be applied to the now-dominant COVID-19 variant.
Speaking with the media about the research, Prof. Jonathan Reid, the study’s lead author said, “People have been focused on poorly ventilated spaces and thinking about airborne transmission over meters or across a room.
“I’m not saying that doesn’t happen. But I think still the greatest risk of exposure is when you’re close to someone,” he said.
The findings suggest that the risk of getting infected by particles suspended in the air depends not only on how many there are floating around but also on their “freshness,” Denis Doorly, an expert in fluid mechanics at Imperial College London who was not involved in the research, told Insider.
Doorly specified, however, that this does not take away from the importance of ventilation as “infectivity does not diminish to zero even after long times.”
Experts, however, noted that it is still unclear whether the study findings can be repeated if moved from a laboratory setting to the real world.