To wear N95 masks, or not to? That is the dilemma more than a billion Indians face now. With the news headlines flashing “The government wants you to stop wearing N95 masks”, everyone who bought N95 masks at very steep prices, are at a loss regarding what to do. But, there’s a catch.
The Centre has written to all states and union territories warning against the use of N-95 masks with “valved respirators” by people, saying these do not prevent the virus from spreading out and are “detrimental” to the measures adopted for its containment.
The Director-General of Health Services (DGHS) in the Ministry of Health, in a letter to the Principal Secretaries of health and medical education of states, noted that it has been observed that there is “inappropriate use” of N-95 masks, particularly those with valved respirators, by the public other than designated health workers.
The DGHS referred to the advisory on the use of homemade protective cover for face and mouth available on the website of the Ministry of Health.
“It is to bring to your knowledge that the use of valved respirator N-95 masks is detrimental to the measures adopted for preventing the spread of coronavirus as it does not prevent the virus from escaping out of the mask. In view of the above, I request you to instruct all concerned to follow the use of face/mouth cover and prevent inappropriate use of N-95 masks,” DGHS Rajiv Garg said in the letter.
But therein lies the confusion. In the market, or on e-commerce sites, valved masks are deemed to be superior and are usually considered to be better for prolonged use, since it lets the air out more, compared to N95 masks without valve which gets suffocating after a while to wear.
The government had in April issued an advisory on the use of homemade protective cover for face and mouth, asking people to wear it, especially when they are in outdoor conditions. The advisory stressed such face covers must be washed and cleaned each day, as instructed, and stated that any used cotton cloth with three layers can be used to make this face cover.
The color of the fabric does not matter but one must ensure that the fabric is washed well in boiling water for five minutes and dried well before making the face cover. Adding salt to this water is recommended, it said.
However, compared to homemade masks, N95 masks are far superior. N95 masks are worn mostly by healthcare workers and are known to offer the highest level of protection against airborne infections, but they don’t prevent or filter 100%. N95 masks filter about 95 percent of particles smaller than 300 nanometres (1 nm is a billionth part of a meter). SARS-CoV-2, the virus that causes Covid-19, however, is in the size range of 65-125 nm.
The valve or the raised plastic gasket found in some N95 mask models filters the air inhaled by the person and blocks the entry of pathogens suspended in the air. The valves allow easier exhalation than traditional masks, prevent humidity, reduce heat, and carbon dioxide build-up inside the mask.
According to Dr. Ajit Kumar Das, the valve becomes a pocket of infection as it is a ‘one-way’ mechanism and exhaled air passes unfiltered into the environment. “The purpose of a mask is not only that it reduces the possibility of the virus getting inside the respiratory tract but also prevents the aerosols from spreading in the surroundings. Through the valve, exhaled air passes unfiltered into the environment and has the potential of taking coronavirus droplets with it, putting others nearby in the risk of contracting the infection,” Dr. Das told The Indian Express.
Doctors have been discouraging the use of N-95 masks with exhaled valves in patient-management, said Dr. Vikas Maurya, director & head, department of pulmonology & sleep disorders, Fortis Hospital, Shalimar Bagh, New Delhi to The Indian Express. “If a COVID-19 patient is exhaling through the valve in the mask and there is another person in front wearing only a cloth mask, it does not really eliminate the risk of being infected. So at our hospital, we ensure people in the COVID wards are wearing normal N-95 masks without valves,” he added.