The market today is flooded with masks claiming to provide you with the ultimate protection against the coronavirus. A recent study by researchers at Duke University, U.S. has identified the face masks which are the most effective at preventing the spread of droplets. 14 types of face coverings or masks were examined by a low-cost laser device developed by the Duke University researchers.
According to the research, N95 masks without valves or respirators are the most effective and the ones made from fleece and bandanas are the least effective. In fact, wearing the latter is worse than not wearing any sort of mask. The lead author of the study, Martin Fischer says, “Surgical masks are commonly worn by medical personnel and have received a fair amount of testing in clinical settings. But there was no quick, easy, and cost-effective way to demonstrate the effectiveness of such a wide variety of other mask types like the ones made out of loose fabrics.”
How Does the Experiment Test the Efficacy of Face Masks?
For the purpose of the study, the researchers designed an inexpensive laser device. This device can measure the exact amount of droplets that escape from different masks whenever the user speaks. The experimental setup consists of a black box, a laser, a mobile phone camera, and a lens. All these equipment amounts to a total of $200 which is super affordable.
For the test, an individual was asked to wear different masks and then stand in a dark enclosure. Then the person was asked to repeat the phrase “stay healthy, people” five times while aiming towards the laser beam. This beam scattered the light that was released from the speech droplets. These droplets were recorded using a mobile camera and the droplets were counted using a computer algorithm.
The researchers said, “Companies and manufacturers can set this up and test their mask designs before producing them, which would also be very useful.” The masks were ranked according to the number of droplets released by them from a scale of 0.0 to 1.0.
What Did the Results Reveal?
The results revealed that N95 masks lacking any sort of valves and respirators are the most effective at protecting you from coronavirus. These are usually reserved for frontline coronavirus warriors. According to the researchers, “Filtered, non-valved N95 masks performed far superior to valves ones because the exhalation valve opens for strong outward airflow. It can decrease protection of persons surrounding the wearer.”
The three-layer surgical mask came in after the N95 mask in terms of efficacy. The third and fourth spot was retained by the polypropylene masks- the cotton-polypropylene mask and the two-layer polypropylene apron mask.