Dealing with Covid: Heating may effectively disinfect N95 masks, making them reusable for 50 cycles

Because of the shortage, many healthcare workers have to wear the same mask repeatedly.

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Heating the mask at 85° Celsius for 20 minutes allows fabric to be treated 50 times without loss of filtration efficiency.
LOS ANGELES: Heating may be the best way to disinfect N95 masks for reuse, according to a study which found that doing so preserves their filtration efficiency for 50 cycles.

Since the outbreak of the COVID-19 pandemic, N95 face masks have been in short supply, said the researchers, including those from Stanford University in California, US.

Healthcare workers, in particular, desperately need these masks to protect themselves from the respiratory droplets of infected patients, they said.


Because of the shortage, many have to wear the same mask repeatedly, according to the researchers.

The study, published in the journal ACS Nano, tested several methods for disinfecting N95 materials, finding that heating them preserves their filtration efficiency for 50 cycles of disinfection.

The researchers noted that N95 masks contain a layer of "meltblown" polypropylene fibres that form a porous, breathable network.
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To help capture smaller particles that could slip through the holes, the fibres are electrostatically charged, they said.

The US Centers for Disease Control and Prevention has recommended several methods for disinfecting N95 masks, such as heating, ultraviolet (UV) radiation and bleach treatment, the researchers said.

However, so far these methods have not been tested extensively, especially for multiple rounds of disinfection, they said.

The researchers wanted to compare five of the methods that could reasonably be used within a hospital setting to see how mask materials hold up to repeated disinfections.
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While analysing N95 masks, they examined pieces of the meltblown fabric used to make these masks.

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The researchers treated the material with a particular disinfectant and compared its ability to filter aerosol particles - resembling respiratory droplets, but lacking coronavirus - before and after disinfection.

The team found that spraying the fabric with an ethanol or chlorine bleach solution drastically reduced the filtration efficiency after only one treatment, from about 96 per cent to 56 per cent (ethanol) or 73 per cent (bleach).

A single steam treatment maintained filtration, but five steam treatments led to a sharp decline in efficiency, the researchers said.

UV radiation allowed up to 20 cycles of disinfection, however, administering the exact dose of UV that kills the virus without damaging mask materials could be problematic, they said.

The researchers said best disinfection method appeared to be heating.

For example, heating at 85° Celsius for 20 minutes allowed the fabric to be treated 50 times without loss of filtration efficiency, they said.

However, frequently donning and removing N95 masks could affect fit, which also impacts performance, the researchers said.

World Hand Hygiene Day: Sanitisers Are Better Than Soaps, And Other Myths Busted
1/6

Keeping your hands clean menas staying healthy. As easy as it appears, washing hands come with a lot of dos and don'ts that people are not aware of.



On World Hand Hygiene Day, here's a list of facts that will ensure you always choose the right way to wash your hands.

Keeping your hands clean menas staying healthy. As easy as it appears, washing hands come with a lot of dos and don'ts that people are not aware of.On World Hand Hygiene Day, here's a list of facts t..
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Fact: You don't need an antibacterial soap for clean hands. For regular use, pick any hand soap. Antibacterial soaps should be only used when a person is ill or in healthcare places where patients have poor immunity. If you have pets at home, antibacterial soap makes sense.

However, avoid overusing antibacterial products as it can drastically reduce healthy bacteria living on your skin. Moreover, using them excessively can also make your body less effective in fighting new germs.
Fact: You don't need an antibacterial soap for clean hands. For regular use, pick any hand soap. Antibacterial soaps should be only used when a person is ill or in healthcare places where patients ha..
Read More
Fact: Hand sanitisers (with 60% alcohol content) should be used if you don't have access to water and soap. While sanitisers only remove some germs quickly for some time, using soap and water to wash hands can keep them away for a long time. Sanitisers should be applied till your hands are dry, which takes merely 20 seconds.

Also, the effectiveness of sanitisers drops when used on greasy or dirty hands.
Fact: Hand sanitisers (with 60% alcohol content) should be used if you don't have access to water and soap. While sanitisers only remove some germs quickly for some time, using soap and water to wash..
Read More
Fact: Just remember 20 seconds of scrubbing every time you plan to wash your hands. In case you are not sure how long 20 seconds are, just hum the 'Happy Birthday' tune in your head, twice. Since hand sanitisers are not enough in removing harmful chemicals, it is important to spare 20 seconds to wash your hands with a soap as it enters the cell wall and kills all viruses and bacterias.
Fact: Just remember 20 seconds of scrubbing every time you plan to wash your hands. In case you are not sure how long 20 seconds are, just hum the 'Happy Birthday' tune in your head, twice. Since han..
Read More
Fact: While moisture attracts bacteria, the Global Hygiene Council had finally revealed that one should wash his/her hands over six times daily. If it is hard to keep track, just remember washing hands before meals and after visiting the toilet.

Also, watch out for signs of excessive hand wash. If you are particular about cleanliness and fear dirt/germs, your concerns can manifest into obsessive-compulsive disorder (OCD), which is a type of anxiety disorder.
Fact: While moisture attracts bacteria, the Global Hygiene Council had finally revealed that one should wash his/her hands over six times daily. If it is hard to keep track, just remember washing han..
Read More
Fact: It's not just your home toilet. Your kitchen holds six of 10 spots for germiest areas at home. Scientists say kitchen cloth/sponge, kitchen sinks, toothbrush holders, bowls of pets, coffee maker, faucet handles, toys of your pets, kitchen counters, knobs of the stove, and vegetable chopping boards are some of the dirtiest spots at home.

Also, avoid touching your eyes, nose or food after coming in contact with these surfaces.

(Inputs from www.cdc.gov & www.aurorahealthcare.org)
Fact: It's not just your home toilet. Your kitchen holds six of 10 spots for germiest areas at home. Scientists say kitchen cloth/sponge, kitchen sinks, toothbrush holders, bowls of pets, coffee make..
Read More

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