新测试：防污染口罩能用多久？

《新测试：防污染口罩能用多久？》有24条评论

1. Does washing the outer side or the inner side (that touches your face) of the n95 diminish the mask’s ability to filter small particles out…. i.e. by somehow condensing or compressig the “mesh” matrix that the mask is made of? I’m thinking washing with soap and hot water and rinsing with hot water and drying them in the sun.

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   • Hi Sandra. Song here. For N95 and similar masks: do not wash them. It damages them and they’re not able to filter out as many particles. And here is why you shouldn’t wash masks..

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2. Starting in March, I ordered 1000 N95 masks which I donated to our local Sheriff’s department. After speaking with the group responsible for distribution, the Sheriff’s department was the most needy as they run the local jail and have medical, corrections, inmates and support staff that along with regular policing come in direct contact with infected individuals. My advice (put in writing) in each 2 mask set was to spray the outside of the “used” mask with a solution of 1/3 bleach to 1 gallon water and let air dry (as per CDC website) while using the second mask. Reading your tests about used masks made the advice more acceptable except I now wonder about the affect of the bleach solution on the masks.

   Any information about the viability of using the bleach solution the CDC recommends On masks?

   Also, I think it’s important to point out that any mask with a valve is obviously more comfortable to wear but if the individual wearing it is infectious it does nothing for the people close by since the exhaled air is not filtered.

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   • Hi Roman, Liz here from Smart Air. If you just use it in your daily life, it can be wear multiple times as long as you disinfect it properly. We haven’t got time to test various disinfection methods people are suggesting. My concern is using the bleach may harm the material thus decrease the mask filtration efficiency. But here is an article with how we would suggest to disinfect your mask: https://smartairfilters.com/en/blog/disinfect-clean-n95-mask-virus-coronavirus/ If you are a healthcare professional, please follow the CDC or hospital protocol.

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3. Don’t throw away you mask when the straps are loose/broken, replace it with a fabric one. You can staple it or even sew it: https://imgur.com/2BlRCoc To avoid breaking them at the wrong time (e.g. at the checkout of a store during a covid pandemic…), it is better to add the new fabric straps even before the first use. Then you let the newly added elastic hang behind your neck, until one of the red elastic breaks. You don’t need special staples, those of a mini paper stapler are sufficient. Remember to put 2 staples on each side, lengthwise.

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4. Bravo! I’ve been looking for this information for a while. I thought the masks would get better at filtering as they became more full (like a HEPA filter) but I couldn’t find any information, except for the old, “that’s what they told us at the hospital I worked at”.

   Thanks for posting and… Stay Healthy

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5. I am in the USA; I am a critical care registered nurse sine 1991; I cannot find the Venus V-430 SLV anywhere; where can i find a reputable place to purchase? since they are reusable, I am very interested in finding a good reusable mask that is durable as I am taking care of covid-19 patients in the ICU in ‘not ideal’ situations to say the least; I need a very good reusable mask; please help?

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   • Hi Steven, Liz here. Check out this article on Lancet: https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30003-3/fulltext
     If you have multiple N95 masks, leave them out under the sun and rotating usage of the masks should work. Here is an article on how UV light can disinfect the virus: https://smartairfilters.com/en/blog/uv-light-disinfects-masks/

     You work in an environment with highest risk. As long as there are new masks, I strongly recommend to follow the healthcare protocol instead of thinking of ways to reuse a contaminated mask.

     Thank you for everything you are doing in this battle. Best wishes to you and your coworkers from all of us at Smart Air.

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     • thank you very much; we have no choice but to reuse masks as there is a shortage; I am trying to find suitable n95 or higher masks with an exhalation valve; it seems the venus v-430 was perfect… but i cannot find it… nor any high quality n95 or higher mask for that matter.

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       • I just ordered 2 packs from this store , it showed up in a week , seems to be good quality, thicker than the one I bought at Walmart, but much more expensive!!!!! I guess they are either hard to find or expensive. I don’t trust the home made ones , especially when we have to go back to work https://hygenyx.com/products/3-ply-disposable-face-mask-50-pack?from=timeline&isappinstalled=0

       • If doubled cotton is used for a face mask, what should the minimum thread count per square inch be?
         Faye

     • I am a nurse and working in the hospital. I have asthma and am caring for outpatients. Some patients may be no symptomatic carriers…. I have N95 masks I bought a few weeks ago and have rotated masks and put them in the sun and also lightly sprayed with Clorox …. is the Clorox a good idea ? Also it rained and they got wet…so it I dry them again are they still effective ?

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       • Hi Janine, washing mask is not a good idea so I doubt that once the mask is wet the filtration rate is affected: https://smartairfilters.com/en/blog/washing-masks-effective-virus/

         We haven’t done test on using Clorox, so I don’t have any data for now. We do have an article on how simply leave the masks out there and dry would help to disinfect them: https://smartairfilters.com/en/blog/disinfect-clean-n95-mask-virus-coronavirus/

         Hope this helps! And best regards from all of us at Smart Air for the work you’ve been doing on the frontline! Stay safe!

       • Activated carbon layer will fill with water and lose it’s grab ability for viruses.

       • I put mine filter up on my car dashboard so the sun can disinfect it,though the windshield probably blocks some of the uv.

6. I have pm 2.5 filters and am making my own masks out of cotton cloth with inserts for those filters; cotton ties and a metal piece to pinch the nose area closed. Are these going to be effective at all in your opinion? I get a great fit but don’t know if just a pm 2.5 is effective. Please help since I am making these for nurses.

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7. Hi, thanks for the detailed studies, analyses and results.
   Perhaps you may also mention or analyze about any new nano-filtering material that can be lighter and not too expensive, which can be washed with soap to extend its life. Are the filters you used not washable i.e. their factory made fibres get spoiled if they are washed? Because news reports suggested that soap-wash of hands is even better than sanitizer wash to get rid of corona virus.

   Thanks a lot,
   Keep up the good work !!

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   • Hi Susheel, we had this article on whether you should wash your mask: https://smartairfilters.com/en/blog/wash-n95-mask-effective-virus/

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8. Great test! What about bacteria starting to grow on the mask if you use it for too long? Might that cause a health hazard? Can you sterilize the mask and kill bacteria and viruses growing on it using high heat? If so, what could you use? A hair dryer? Heat gun? Oven? Put it out in the sun and let the UV lights kill them? This question is important since there seems to be a shortage of masks and people will need to know how to make them last longer and safely handle them, etc.

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   • I would like to know that too. They say a 10 min exposure at 60°C is enough to kill the coronavirus, so maybe an oven would be enough. I just hope the temp doesn’t damage the filter.

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   • Microwave them?

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     • We’ve just published an article on microwaving masks, feel free to check it out! https://smartairfilters.com/en/blog/microwave-mask-disinfect-covid-virus/

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9. Thanks for all the work you guys are doing! I had a question. How come masks with such a thin fabric can stop 99.95% of PM2.5 particles, but it requires a hefty HEPA filter when it comes to indoor air purifiers? Wouldn’t it make more sense to strap the same fabric masks are made out of onto the purifiers if they’re that good?

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   • Hi Parth, here is our new article, there is a session explains how masks works (there is also an video): https://smartairfilters.com/en/blog/wash-n95-mask-effective-virus/

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