One study shows that tapered fit masks and home liners made of multiple layers of fabric are the best designs to stop the spread of the coronavirus.
Researchers at Florida Atlantic University examined different materials and designs to find the best option to stop the spread of the virus-carrying droplets.
These drops are expelled when someone with a COVID-19 coughs or sneezes, and tests show that loosely folded masks and bandana-style liners perform poorly.
According to the researchers, this is because those designs provide minimal stopping ability for respiratory drops that can extend up to 8 feet if not clogged.
They found that a simple kerchief-style mask can prevent droplets from passing more than 3 feet, but a well-fitted cotton fabric sewn-in mask stops the droplets at 2.5 inches.
Smaller respiratory drops are filtered through a face mask constructed from a handkerchief-folded handkerchief, which extends up to three feet from the wearer
With the sewn quilted cotton mask, the drops traveled 2.5 inches, considerably less than the 3 feet of a bandana mask
The pathogen responsible for COVID-19 is found primarily in the respiratory droplets expelled by infected individuals by coughing, sneezing, or even talking and breathing, the Florida team explained.
This explains the rationale for governments to recommend facial coatings, to reduce the risk of cross-infection from infected people to healthy people.
On June 15, the UK government made facial coatings compulsory on public transport in England; Other countries have gone further, demanding them when they are in public.
Despite this, authorities have yet to announce guidelines on the best varieties of face masks to reduce the spread of COVID-19.
The study’s principal investigator, Dr. Stella Batalama, of Florida Atlantic University, said they wanted to discover the best options to reduce the spread of COVID-19.
“Our researchers have shown how masks can significantly reduce the speed and range of respiratory droplets and jets,” said Batalama.
“In addition, they have discovered how emulated cough can travel remarkably beyond the currently recommended distance guide.”
The research team used a technique called ‘flow visualization’ in a laboratory setting where they used a mixture of distilled water and glycerin to generate a synthetic mist to mimic cough drops.
They used a mannequin to simulate coughs and sneezes, before visualizing the drops expelled from their mouth.
They tested a variety of masks that are available to the general public and that do not deplete the medical grade masks and breathing devices that are vital for healthcare workers.
This included a single-layer bandana-style cover, a homemade mask sewn with two layers of cotton cloth, and a non-sterile cone.
By placing these various masks on the mannequin, they were able to trace the paths of the drops and demonstrate how differently they perform.
The results showed that slightly folded face masks and bandana-style liners provide minimal stopping ability for the smallest respiratory droplets.
While well-fitting home masks with multiple layers of quilted fabric and conventional cone-style masks proved to be the most effective.
They were able to “significantly” reduce the speed and range of the breathing jets, albeit with some leakage through the mask and small gaps at the edges.
Without a mask, the droplets traveled more than eight feet, with a scarf, they traveled three feet seven inches, and with a folded cotton scarf, they traveled 1 foot, 3 inches.
The cough drops traveled only 2.5 inches when covered by a sewn quilted cotton mask, and with the tapered-style mask, the drops traveled approximately eight inches.
Study leader Dr. Siddhartha Verma, assistant professor at FAU, said they wanted to convey to the public the importance of social distancing and facial masks.
“Promoting a widespread awareness of effective preventive measures is crucial at this time as we are seeing significant spikes in cases of COVID-19 infections in many states, especially Florida,” he said.
Importantly, the simulated coughs discovered were able to travel remarkably beyond current distancing patterns, between three and six feet.
When the mannequin was not equipped with a mask, they projected drops of up to 12 feet in approximately 50 seconds with drops suspended in the air for up to three minutes.
The researchers said their observations suggest that current patterns of social distancing may need to be increased rather than reduced.
With a folded cotton scarf, the drops traveled 1 foot, 3 inches, according to the team.
In the UK, Boris Johnson announced a new rule of 1 meter more, where two meters (or 6 feet) were still required but could be released with the addition of protective gear such as face masks and protective screens.
The study’s author, Professor Manhar Dhanak, said: “ We found that, while unobstructed turbulent jets were observed to travel up to 12 feet, a large majority of the ejected droplets fell to the ground at this point.
“It is important to note that both the number and concentration of the drops will decrease with increasing distance, which is the fundamental reason behind social distancing.”
In addition to COVID-19, respiratory droplets are also the primary transmission medium for other viral and bacterial diseases.
With the cone style mask, the drops traveled approximately 8 inches, the second best performing mask
This includes conditions like the common cold, influenza, tuberculosis, SARS, and MERS, according to Florida researchers.
These pathogens are carried by respiratory droplets, which can reach healthy individuals and cause direct transmission.
When pathogens land on objects, they can cause infections when a healthy person comes in contact with them.
Dr. Batalama, from the FAU’s College of Engineering and Computer Science, said the study findings highlight the need for key workers to perform simple experiments to test the quality of their PPE.
He added: “His research describes the procedure for setting up simple visualization experiments using readily available materials, which can help health professionals, medical researchers, and manufacturers to evaluate the effectiveness of face masks and other personal protective equipment qualitatively.”
The findings have been published in the journal Physics of Fluids.
THICK EXPERIMENT: THE MICROBIOLOGIST TOS, SNEEZES AND SING IN A PETRI PLATE TO DEMONSTRATE WHY THE MASKS WORK IN COVID-19
Disturbing images have been shared on social media showing the importance of a face mask to delay the spread of the coronavirus.
Dr. Richard Davis, a clinical microbiologist, shared the grim images as a way to demonstrate how vital the masks were when you couldn’t socially distance yourself.
He sneezed, coughed, spoke, and sang on agar cultures held close to his face – these are gelatinous substances from red algae in a Petri dish.
The objective was to see how the droplets of bacteria spread in the crops from different types of expulsion from the human mouth and at different distances.
Disturbing images showing the importance of a face mask to delay the spread of the coronavirus have been shared on social media.
“First, he sneezed, sang, talked, and coughed into an agar culture plate with or without a mask,” he said, adding that he then had to wait for the bacteria to grow.
When the bacterial colonies formed, they began to show where the drops landed – a mask blocks virtually all of them, he said.
Currently, the UK advises people to stay six feet away when in public, but this relaxes three feet more from July 4, focusing on the need for protective gear if they cannot adequately distance themselves socially.
Then he began to demonstrate the importance of social distancing.
For the second demonstration, he placed open bacteria culture plates 2, 4, and 6 feet away and coughed (loud) for about 15 seconds and repeated without a mask.
When the bacterial colonies formed, they began to show where the drops landed – a mask blocks virtually all of them, he said.
“The drops landed mostly less than 6 feet away, but one mask blocked almost all of them,” Davis said.
He said this is not the typical way to model the spread of the coronavirus, but rather a way to show the effectiveness of facial coatings in decreasing the spread.
The normal bacteria colonies in his mouth and throat showed the spread of large respiratory drops, like the kind of scientists who think he primarily spread COVID-19, and “how a mask can block them,” Davis said.
“ The masks as a political / social litmus test or used to embarrass those who don’t wear them (or disabled people who can’t really wear them!
‘We wash our hands after using the bathroom and wipe our noses with tissue. Masks / face shields should be just another standard act of hygiene.
.
