‘Double masking important now more than ever’
MUMBAI: Wearing two masks at a time is an effective technique to improve the fitting and protection provided to the face. Yet, as Covid-19 cases decline in Mumbai, many of us who had started using double masks, have now returned to single masks. Double face coverings, however, are important now, more than ever, as the highly infectious Delta variant continues to spread at the same time when the city is unlocking, and only 10% of the city’s population is fully vaccinated.
As we breathe, talk, cough or sneeze, we expel tiny droplets into the air. Masks mainly help in trapping these droplets into the fibrous layers.
An Indian Institute of Technology (Iit)-bhubaneshwar study published in the journal Physics of Fluids last month stated that combining two masks provides an additional layer of protection and better fitting to minimise the leakage of droplets expelled during coughing, sneezing, talking, and breathing. Researchers used mannequins along with breathing simulators for the study. They used a combination of water and glycerin to create a fog to visualise the droplets. The IIT researchers concluded that a combination of N95 and a cotton mask was the best for safety as well as breathing comfort. While other combinations like surgical mask and N95 or surgical mask and cotton mask minimised leakage, the wearer required more effort to breathe.
According to an Iit-bombay study published in October 2020, cough of a Covid-19 infected person can contaminate a large volume of surrounding air with the virus. The size of cough clouds is nearly seven times smaller when one wears a surgical mask and nearly 23 times smaller with N95 mask, the study stated. “With an additional mask, one can further reduce the contamination,” said Rajneesh Bhardwaj, associate professor, department of mechanical engineering at Iitbombay and co-author of the study.
As offices open up, mandatory double masking in closed environments can help in reducing the risk of infections. “One mask does not seal the area around the nose and mouth properly,” said Dr Rahul Pandit, an intensive care specialist and member of Maharashtra’s Covid-19 task force. “It is the second mask that helps seal the mask underneath,” he said.