Hairdressers, beauticians and medical professionals who are infected with COVID-19 can spread the virus to patients and their clients just by talking, according to a study.
The images show how particles coming out of a person’s mouth while talking can spin and spread in the vicinity of other people, even when wearing a mask.
Previous studies have found that rapid removal of droplets and aerosols, such as those from sneezing or coughing, dramatically increases the risk of spreading the virus. But the new study supports the theory that speech provides enough strength for the extracted particles to be a risk of infection, writes the Daily Mail.
Japanese researchers from Aoyama Gakuin University in Tokyo used smoke and laser light to track distant breathing. They recreated scenarios when one person leans on another person, such as when they wash their hair or perform a dental examination.
One volunteer leaned over another person and exhaled after breathing in smoke from an adapted electronic cigarette which produced artificial smoke consisting of droplets about one-tenth of a micrometer in diameter, similar in size to a virus particle.
The chemicals in the smoke mixture – a mixture of glycerin and propylene glycol – create a cloud that scatters light when illuminated by a laser. This allows the visualization of airflow patterns.
In the study, published in Physics of Fluids, the participant wore a mask or was without a mask while standing, sitting, face down or lying face up. They were instructed to constantly utter a typical Japanese greeting in a business setting after inhaling the vapors.
The study took place in a hair salon at Yamano College of Aesthetics in Tokyo and the attitudes studied were specially chosen to simulate customer service roles.
“A considerable amount of similar face-to-face contact would occur not only in the field of beauty but also in long-term and medical care,” said lead author Keiko Ishii.
The study found that air exhaled by a person who was not wearing a mask moves down due to gravity and would fall on a patient or client.
Investigators also found that face shields can prevent any aerosol leaking around the technician’s mask from traveling to the client.
“The shield of the face stimulated the increase of exhalation. Therefore, it is more effective to have a mask and face shield when offering services to customers “, said Ishii./Express