Explained: Why N95 Masks With Valves Are Ineffective Against COVID-19

The health ministry wrote to state health and medical education secretaries to discourage the use of N95 masks with valves as they do not filter exhaled air

India's health ministry wrote to states on Monday to discourage the use of N95 masks with valves as a form of protection against COVID-19 saying that valves do not stop the virus from being exhaled in the air.

The Ministry of Health and Family Welfare also remarked that they witnessed that these masks are inappropriately used by public other than designated health workers.

These N95 masks are labelled to be used for health workers as they are the most vulnerable to contract the virus. For the general public, normal homemade cloth masks are enough to prevent the spread of the virus.

Why Do Some N95 Masks Have Valves?

N95 masks are respirators that prevent inhalation of 95% of hazardous materials from the air. They keep away airborne particles and should only be worn in areas where there is no presence of oil. These masks are not resistant to oil. The 95 stands for the amount of airborne particles that the masks can keep away. In most places, health care workers have to be trained to pass a test to confirm that the mask is sealed.

Valved masks make it easier to breathe through by also reducing the moisture which builds up in the face mask. It also keeps the face cooler.

Why Valved Masks Should Not Be Used For COVID-19?

The valves have their disadvantages, too. The problem with valves arises as they filter the air being inhaled, but do not filter the air being exhaled.

BOOM spoke to Dr. Prashant Chhajed, chest physician, Lung Care and Sleep Centre, Mumbai who explained why the valves do not work.

"Not just for N95, any masks with valves beat the purpose of controlling the spread of infections. The air exhaled by an individual who is infected has the potential to transmit the virus. We are not recommending masks with valves as they protect the individual, but do not protect others," explained Dr. Chhajed.

This reasoning is corroborated by the Mayoclinic, an American nonprofit academic medical center where they have said that unfiltered air is released through these masks when a person exhales. It does not control or prevent the spread of infection if an infected person decides to wear a mask with a valve. The virus particles are exhaled in the air through the valve increasing the risk of contracting COVID-19. Even health workers are asked to wear the masks without valves. It also said that some areas have banned N95 masks with valves.

Even the Centres for Diseases Control and Prevention, USA vouches for the use of N95 masks/ respirators for healthcare professionals but with a note of caution. In a section addressing frequently asked questions, the CDC warns that N95 respirators with valves should be avoided in areas which require sterile environments as they exhale unfiltered air.

What Does The Letter Say

Along with warning about the inappropriate use of N95 masks and inhibiting the use of masks with valves, the ministry has also pushed for the use of homemade masks.

The Indian Health Ministry issued guidelines where it recommends homemade cloth masks for daily use after reports of people hoarding masks. In the months of March, April, when the pandemic had just begun in the country, multiple news reports discussed the lack of surgical masks, N95 masks, and Personal Protective Equipment for medical professionals in the country. There were even reports of masks being sold at exorbitant prices in the market which led to the inclusion of masks in the Essential Commodities List. However, on July 7, the Ministry of Consumer Affairs, responsible for maintaining the list of Essential Commodities decided to remove them from the list.

Homemade reusable face covers were not recommended for health workers as well as people who were exhibiting symptoms of COVID-19. People in close proximity of COVID-19 patients were also asked to not use these reusable face covers.

There have been many myths surrounding masks that BOOM has been actively debunking since February, 2020.

Also Read:Wearing Face Masks Will Not Cause Fungal Lung Infections

Also Read: Viral Post Makes Numerous False Claims About Effects Of Face Masks


1. Mayo Clinic: https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-mask/art-20485449

2. Centres of Disease Control and Prevention: https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use-faq.html

Updated On: 2020-07-21T17:40:45+05:30
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