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masks they have become something essential in our lives from night to the morning after the pandemic of coronavirus burst into our lives. First they sold out in the pharmacies, after, there was a wide debate about its desirability and its compulsory and are now part of our belongings each time we left the house. There are many types: disposable, cloth, surgical,… there have been several studies on how the masks sanitary protect against Covid-19 , but few data exist on what is the effectiveness of the masks fabric home used by a wide range of public.
Now, a study of the Faculty of Engineering and Computer Science of Florida Atlantic University (FAU), published in the journal “Physics of Fluids” comes to shed light on the matter. Light and especially direct visualization of how coughing and sneezing spread even despite the masks, though they be of a material or another, the dispersion of droplets that contain SARS-CoV-2 can be very different.
Experiment with mannequins that cough
The researchers used dummies to set them to different types of masks that are readily available to many people but that are not seen in the field of health. In particular, used for the experiment to be a simple scarf or a bandana ; cotton handkerchief folded over itself; a mask homemade stitched with two layers of cotton fabric and padded in the center, and other style cone, non-sterile, available in pharmacies.
Later, simulated coughing or sneezing of the mannequin using a mixture of distilled water and glycerin to reproduce the “cloud” of droplets of saliva that is formed with these actions. Each cough or sneeze with the different masks was enlightened, a a laser beam to be able to make a visualization as detailed as possible of the drops that escaped the masks homemade.
Results of the tests On the face masks that are a cotton handkerchief folded in half, the drops escaped by the tissue up to 40 centimeters – Florida Atlantic University, School of Engineering and Sciences of the ComputaciónCon the mask type cone non-sterile drops reached the 20-centimeter – Florida Atlantic University, School of Engineering and Sciences of the ComputaciónCon the mask of quilted fabric were able to filter particles by the parties ill-fitting and even the fabric, although not reached more than six centimetres – Florida Atlantic University, College of Engineering and Computer Science
this is how the researchers found that without a mask of any type, drops traveled even more from the two metres recommended: reached nearly two meters and a half, and in some cases even a meter more . With a simple bandana , remains were found in one meter away. With the scarf of folded cotton to half the trip was reduced to 4 inches . In regard to the mask a homemade, quilted fabric , the remains came to the six inches . Finally, the mask cone was not effective in the 20 centimeters .
“The results show that the masks folding masks style bandana provide a minimum capacity of detention for the respiratory droplets in spray smaller” write the researchers. “The masks homemade tight with multiple layers of quilted cloth, and the masks of style of cone proved to be the most effective to reduce the dispersion of droplets”, continue, if well affect that even with all the saliva you can escape through the spaces between the mask and the face or even passing through the material .
Up to 3 metres at times extreme
The results also showed that when the dummies were not wearing masks of any kind, the drops could travel up to more than three and a half meters in just 50 seconds . Found in addition in the laboratory, these particles could remain suspended in the air for up to three minutes , which indicates that social distancing measures may need to be updated to take account of the transmission of pathogens based on aerosols.
“we found that although it was observed that the turbulent jets without obstacles were traveling up to 12 feet (3.4 metres), a large majority of the drops expelled fell to the ground at this point,” says Manhar Dhanak , responsible for the study along with fellow Siddhartha Verma , and John Frakenfeld . “It is important to note that both the number and the concentration of the droplets will decrease with the increase of the social distance, the fundamental reason for applying these practices.”
Masks more distancing measures
in Addition to the new coronavirus, fluids, respiratory also are the main means of transmission of other viral diseases, and bacterial, such as the cold common flu , the tuberculosis , the SARS (severe acute respiratory syndrome) and the MERS (respiratory syndrome in the Middle East), among others. These pathogens are involved within the droplets, which may fall in healthy individuals and lead to direct transmission, or in objects, which can also cause the infection if a healthy individual comes in contact with them.
“in Addition to providing an initial indication of the effectiveness of the protective equipment, the images used in our study may help to convey to the general public the basics of the guidelines and recommendations of social distancing even using facial masks “, says Verma . “To promote widespread awareness of effective preventive measures is crucial in this moment, as we are seeing significant peaks in cases of infections by Covid-19”, affect.
“The study shows how the masks can significantly reduce the speed and scope of the droplets and jets breathing. Also, learn how to cough emulated can to travel significantly beyond the guide distance of six feet -two meters – currently recommended,” says Stella Batalama , dean of the FAU. “Their investigation describes the procedure for setting up experiments display simple using readily available materials, that can help health professionals, medical researchers and manufacturers to qualitatively assess the effectiveness of face masks and other personal protective equipment”.
