Mask has been a huge demand after the global hit of COVID-19 pandemic. Wearing a mask while you go out in public has become the new normal for everyone. Yet, many doubt the effectiveness of this.
Prasanna Simha Mohan Rao, from the Sri Jayadeva Institute of Cardiovascular Sciences and Research and Padmanabha Prasanna Simha, from the Indian Space Research Organisation in collaboration, started an experiment and visualized the flow areas of coughs under many mouth covering situations. They published their experiment and the findings in the Physics of Fluids journal.
Prasanna Simha Mohan Rao said, “If a person can decrease the amount of how much they infect the environment by decreasing the spread, it’s a far better situation for other healthy individuals who may enter places that have such contaminated areas”.
Coughs are warmer than their surroundings, density and temperature are associated with one another. The researchers used a method called schlieren imaging. The method allows to visualizes the fluctuations in density and captures the pictures of coughs of five test subjects. The team estimated velocity and spread of the droplets by tracing the motion of a cough of successive images.
The researchers were able to find N95 masks to be the most effective that would reduce the spread of a cough and hence the virus. The N95 masks were able to reduce a cough’s velocity by limiting its spread to within 0.1 and 0.25 meters.
The cough can travel up to 3 meters if not covered and, even a normal disposable mask reduce it to 0.5 meters.
He further added, “If a mask does not filter all the particles, we can prevent some of them from travelling far it is better than not doing anything. Any mask is better than not wearing one which would tend for the slow the spread of infection.”
Some of the other examples were remarkable like using an elbow to cover the mouth while coughing is a good alternative. But if it is covered by a sleeve, a bare arm cannot be helpful. As the cough is let to leak through the openings and scatter in various directions.
The duo researchers believe that their findings will be able to help people with what mask to choose as the regular cloth masks are ineffective, but they insist that masks must remain to be used in along with social distancing.
“Social distancing must be followed since masks are not reliable,” Simha stated.
Inputs by : The American Institute of Physics (AIP)