N95 masks with valves can be detrimental for preventing COVID-19: Health ministry
The health ministry today has warned against "inappropriate use of N95 masks, especially those that contain respiratory valves" by the citizens. In a letter to all states and union territories, Rajiv Garg, the director general of health services, ministry of health said "It is to bring to your knowledge that the use of valved respirator N95 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."
Valve masks are okay to combat pollution but not for COVID-19. It filters air ONLY when you inhale, and it expels air in a strong, steady jet, so you’ll infect others if you’re an asymptomatic carrier.
Amid the COVID-19 pandemic, if you step out wearing a valve mask you bought to tackle pollution, you should consider changing it. Health experts have advocated for face masks to prevent COVID-19 spread, but masks with valves only filter inhaled air. So, if you’re a COVID carrier, you will infect others if your mask has a valve.
Arvind Kumar, Chairman, Centre for Chest Surgery and Director in Institute of Robotic Surgery at Sir Ganga Ram Hospital, explains, “In COVID-19, the primary purpose of the mask is to protect others from you. The secondary purpose is to protect yourself. In air pollution, the only purpose is to protect yourself. That is the fundamental difference. In pollution, you need to clean 100% of the air you are breathing in and what you are breathing out can be allowed to go out back into the environment without resistance so that you don't rebreathe your own air. But for COVID-19, you need 100% filtration during exhalation and effective filtration during inhalation.With a valve mask, everything that you breathe through the mask is filtered, but when you breathe out, the valve opens and allows unfiltered air to come out. So, if one is infected with COVID-19 and is wearing a valve mask, they are infecting others.”
Source: Live Mint, TOI