# Are N95 Masks Effective at Filtering Airborne Viruses? **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [February 12, 2023, 10:33pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683 "2023-02-12T22:33:00Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Capn\_Carl](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Capn\_Carl](https://boards.straightdope.com/u/Capn_Carl)\ **Post date:** [February 13, 2023, 1:59pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/21 "2023-02-13T13:59:00Z")
This isn’t rocket science. You can see how such filters work on a larger scale. If your home has filters for heating/cooling, the openings in the filters are much larger than the dust particles that they catch, using electrostatic attraction. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [February 13, 2023, 2:15pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/22 "2023-02-13T14:15:12Z")
> [@Bob\_Blaylock](#): > > > [@Chronos](#): > > > > OK, then how do you explain the experimentally-observed fact that they do, in fact, work? > > How do you explain other studies that clearly seem to show that they do not? Here is the first study to show that mask material (and the material in surgical masks is basically the same as the material in N95s, it’s the construction of the mask and the fit where most of the difference lies) prevents the transmission of covid from live animals to other live animals. > **[Surgical Mask Partition Reduces the Risk of Noncontact Transmission in a...](https://pubmed.ncbi.nlm.nih.gov/32472679/)** > > SARS-CoV-2 could be transmitted by respiratory droplets or airborne droplet nuclei which could be reduced by surgical mask partition in the hamster model. This is the first in vivo experimental evidence to support the possible benefit of surgical... This is from before they even acknowledged aerosol transmission. But this was a practical experiment using animals. There were a number of other studies at the time, for instance, one at a Boston Hospital that found that their masked-at-work staff who were treating covid patients all day had a lower rate of covid infection that the communities that staff lived in. What you got? Because there are a LOT of good studies showing that masks work specifically to reduce the transmission of covid. And if anyone is interested in data on tons of commercially available masks, I highly recommend Aaron Collins’ youtube channel. Here’s a random segment. [![](https://img.youtube.com/vi/N5XnjuPTkgU/maxresdefault.jpg "Mask Review - More KF94s, N95s and more! Clean Well KF94, 3M 9502+") ](https://www.youtube.com/watch?v=N5XnjuPTkgU) He had a PhD in something relevant, and materials to set up a filtering test in his bathroom, and spent a lot of the pandemic doing just that. He also maintains publicly available google spreadsheets with his results. [Aaron Collins on Twitter: “All my data is available at this Google Drive link. I know I have been getting a quite a few messages looking for it. It includes master data set, FAQ, Kid’s mask recommendation and mask images https://t.co/q1H6P2AEhk” / Twitter](https://twitter.com/masknerd/status/1476668499649044484?lang=en) He does test masks with and without the electrostatic charge, by the way. It turns out that alcohol can permanently strip (part of) the charge, and he shows the reduction in efficiency of masks that have been soaked in alcohol vs. those that haven’t been. They still work better than you might imagine (given the size of the holes) without the electric charge, but it’s a big reduction. He also tested water and linked in at least on of his videos to someone who tested artificial sweat, neither of which significantly damage the effectiveness of masks. Good news for those of us who routinely sweat into our masks. ---
**Author:** ![Bob\_Blaylock](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_blaylock/32/3235_2.png) [@Bob\_Blaylock](https://boards.straightdope.com/u/Bob_Blaylock)\ **Post date:** [February 13, 2023, 5:33pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/23 "2023-02-13T17:33:49Z")
  If you look at the box in which whatever mask you are using came, you’ll probably find a warning like this: [![](https://paulthepaperbear.files.wordpress.com/2020/07/ukc-news-10_07_20-23.png) ](https://paulthepaperbear.files.wordpress.com/2020/07/ukc-news-10_07_20-23.png) > WARNING: THIS PRODUCT IS AN EAR LOOP MASK. THIS PRODUCT IS NOT A RESPIRATOR AND WILL NOT PROVIDE ANYPROTECTION AGAINST COVID-19(CORONAVIRUS) OR OTHER VIRUSES OR CONTAMINANTS. Wearing an ear loop mask does not reduce the risk of contracting any disease or infection. User is solely responsible for the selection of appropriate personal protective equipment for the setting and application. Change immediately if contaminated.   The manufacturers of these masks won’t even claim that they offer any protection against COVID or any other viral disease, and in fact, explicitly disclaim any such protection.   That last sentence is kind of interesting, too.  _“Change immediately if contaminated.”_  If you are wearing one of these masks to protect others from what you are breathing out, then the very first time you exhale while wearing one, it is contaminated, and needs to be replaced immediately.  It seems that nobody is thinking about the sanitary aspects of the use and disposal of these masks.  If you’re wearing it to catch pathogens that cause a dreaded disease, then they need, afterward, to be disposed of as hazardous biological waste, not just tossed into normal trash, or worse yet, as happens to too many of them, just tossed on the ground as litter.  Otherwise, it just becomes a different way of spreading the same diseases that you thought you were using it to contain.   Even genuine N95 masks only protect against _“certain particles”_, not really specifying which particles.  I think that the N95 standard only specifies effectiveness against particles down to 0.3 of a micron, which is still bigger than the maximum size of a Corona virus.   And like surgical masks, these are really meant to protect the wearer from particles coming from outside, not to keep particles in coming out from the wearer.  Some of the better N95 masks, in fact, have valves to allow exhaled air to bypass the filter, for easier breathing. ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [February 13, 2023, 5:47pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/24 "2023-02-13T17:47:20Z")
That’s a surgical mask. Surgical masks are intended and worn to reduce your potential for infecting others. That’s why surgeons wear them during surgeries. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [February 13, 2023, 5:48pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/25 "2023-02-13T17:48:11Z")
> [@Bob\_Blaylock](#): > > And like surgical masks, these are really meant to protect the wearer from particles coming from outside, not to keep particles in coming out from the wearer. Um, the whole point of surgical masks is to protect the inside of the patient from the surgeon’s filthy breath. Dunno what masks you are buying, but grabbing the closest box of masks I have (Dr. Puri Micro-Dust Protection Mask, KF94) the back says “Efficacy effect: Protects the respiratory system from particulate matters such as fine dust and source of infection”. And “the inside of the mask is contaminated” refers to stuff you don’t want to breathe in, it doesn’t refer to whatever you just breathed out, at least, not in any normal situation. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 13, 2023, 5:53pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/26 "2023-02-13T17:53:27Z")
> [@puzzlegal](#): > > the whole point of surgical masks is to protect the inside of the patient from the surgeon’s filthy breath. It boggles the mind that a person would be debating the effectiveness of masking when failing to comprehend the most basic concept of medical mask wearing we had pre-covid. Granted, the core purpose of surgical masks does not prove effectiveness for Covid, but anti-maskers act as though the concept of masks reducing disease transmission via breath is ridiculousness. ---
**Author:** ![Bob\_Blaylock](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_blaylock/32/3235_2.png) [@Bob\_Blaylock](https://boards.straightdope.com/u/Bob_Blaylock)\ **Post date:** [February 13, 2023, 6:03pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/27 "2023-02-13T18:03:26Z")
> [@Cheesesteak](#): > > It boggles the mind that a person would be debating the effectiveness of masking when failing to comprehend the most basic concept of medical mask wearing we had pre-covid.   What is mind-boggling to me is how easily so many people were deceived, frightened, manipulated by fear of an overhyped cold/flu bug, to the point not only of allowing, but actually demanding the extreme abuses of government power that have been brought down on us as a reaction thereto.   I think it is undeniable that between the economic sabotage, the destruction of basic freedoms, and the empowerment of government-based criminals, that we have done much, much, much more harm to ourselves as individuals and as a society, than this disease ever had the potential by itself to cause. ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [February 13, 2023, 6:10pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/28 "2023-02-13T18:10:40Z")
> [@Bob\_Blaylock](#): > > I think it is undeniable that between the economic sabotage, the destruction of basic freedoms, and the empowerment of government-based criminals, that we have done much, much, much more harm to ourselves as individuals and as a society, than this disease ever had the potential by itself to cause. And yet, I do deny it. How about that. ---
**Author:** ![Capn\_Carl](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Capn\_Carl](https://boards.straightdope.com/u/Capn_Carl)\ **Post date:** [February 13, 2023, 6:13pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/29 "2023-02-13T18:13:33Z")
Wrong. Surgical masks are designed to catch moisture exhaled by the wearer. That’s why surgeons wear them. They’re also worn by thousands of clean room workers, all over the world, to stop the exhaled droplets from contaminating product. The masks are tested at several levels and under varied conditions. They work. They’re tested by the mask makers, because if they don’t filter as intended, they will fail later when subjected to tests by the customer, like the pacemaker manufacturer that I worked for. Our quality control engineers had to test samples of the masks we bought. If our clean room workers used masks that didn’t stop those droplets, the droplets would contaminate the product, and the pacemaker wouldn’t work as designed. The device you’re using to type out falsehoods on wouldn’t work, either. The masks work. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 13, 2023, 6:34pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/30 "2023-02-13T18:34:44Z")
> [@Bob\_Blaylock](#): > > What is mind-boggling to me is how easily so many people were deceived, You literally don’t know how masks work, or why surgeons wear masks. How is it that you can declare any understanding of the dangers this disease posed, or the validity of the mitigation strategies when you are befuddled by the most basic of disease transmission concepts? ---
**Author:** ![Capn\_Carl](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Capn\_Carl](https://boards.straightdope.com/u/Capn_Carl)\ **Post date:** [February 13, 2023, 7:44pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/31 "2023-02-13T19:44:37Z")
Bob\_Blaylock, you don’t know how filters work, and it looks like you don’t want to know, either. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [February 13, 2023, 8:01pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/32 "2023-02-13T20:01:31Z")
I remember seeing a cool video about how N94 masks can stop large particles (by just blocking them) and very tiny particles (through electrostatic attraction) and that it was medium size particles that were an issue. The way the work is certainly counter-intuitive. Anyway, masks work! > [@Bob\_Blaylock](#): > > overhyped cold/flu bug That overhyped disease has killed millions and counting. If you’re just a run-of-the-mill COVID denier, I’m not sure why anyone here would bother engaging. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [February 13, 2023, 8:12pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/33 "2023-02-13T20:12:03Z")
I was starting to follow the thread and then saw that @Bob_Blaylock referred to the virus, not by any scientific name but rather “#CoronaHoax2020” and “#CoronaHoax”. I can’t see how anyone is going to turn this into a meaningful discussion about Covid when the opposition is speaking about it like that. Honestly, I’m of the assumption that that the pictures are fabricated. Why on earth would someone that thinks covid is a hoax put any time into creating these images. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [February 13, 2023, 8:23pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/34 "2023-02-13T20:23:02Z")
You have certainly convinced _me_…that discussing this with you is a total waste of time and effort. ---
**Author:** ![susan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/susan/32/17537_2.png) [@susan](https://boards.straightdope.com/u/susan)\ **Post date:** [February 13, 2023, 10:40pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/35 "2023-02-13T22:40:55Z")
The mask I wear is Vogmask: > **[Vogmask High Filtering Efficiency Reusable Face Mask](https://www.vogmask.com/)** > > Vogmask, the premier reusable filtering face mask offering high efficiency, comfort, and excellent fit. The website states > PRODUCT CONFORMS to standards in testing at independent testing labs. > 95% Particle Penetration Filtering Efficiency > Viral Filtration Efficiency > 99.9% There were no detected plaques on any of the Andersen sampler plates for this test article. See Test Report at [Technical – Vogmask](http://www.vogmask.com/pages/technical) > Bacterial Filtering Efficiency > 99.9% There were no detected colonies on any of the Andersen sampler plates for this test article. See Test Report at [Technical – Vogmask](http://www.vogmask.com/pages/technical) ---
**Author:** ![Tfletch1](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tfletch1/32/5340_2.png) [@Tfletch1](https://boards.straightdope.com/u/Tfletch1)\ **Post date:** [February 13, 2023, 10:55pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/36 "2023-02-13T22:55:45Z")
> [@Max\_S](#): > > I get that - if particles ‘stick’ to the fibers, via Van der Waals force, and the filter is relatively dense and thick, chances are slim that there will be a large pore from one side of the mask straight through to the other. It’s like if I took a black shirt and folded it over once or twice, then held it up to see how much light bleeds through. Exactly. And @Capn_Carl correctly stated that this works with HVAC or any filtration system. ---
**Author:** ![Bob\_Blaylock](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_blaylock/32/3235_2.png) [@Bob\_Blaylock](https://boards.straightdope.com/u/Bob_Blaylock)\ **Post date:** [February 13, 2023, 10:55pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/37 "2023-02-13T22:55:56Z")
> [@Czarcasm](#): > > You have certainly convinced _me_…that discussing this with you is a total waste of time and effort.   I’m coming to a very similar conclusion.  Most people have chosen the Blue Pill. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [February 13, 2023, 11:00pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/38 "2023-02-13T23:00:15Z")
WTF?? I mean, people have shown you scientific cites and you’re responding with “blue pill”? Why don’t you provide a cite that masks don’t work to filter out the particles that contain the virus? I mean, seriously, provide a cite to back up your claims. Or, accept that you don’t understand the science, but the cites are valid and you’ll reconsider your views. Anything else is just willful ignorance. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [February 13, 2023, 11:14pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/39 "2023-02-13T23:14:02Z")
Well, I have to step away, but I look forward to whatever tome it is that you’re writing. If it’s a response to me, please @ me or I may not see it. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 13, 2023, 11:28pm UTC](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683/40 "2023-02-13T23:28:06Z")
> [@Bob\_Blaylock](#): > > If you look at the box in which whatever mask you are using came, you’ll probably find a warning like this: You’ve convinced me that that particular mask doesn’t provide significant protection against disease. Which is relevant for that particular mask. Look elsewhere on that box, and you know what else you’d find? That it’s not an N95 mask. You will not find both that warning, and the N95 label, on the same package. Ever wonder why that is? [Previous page](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683.md?page=1) [Next page](https://boards.straightdope.com/t/are-n95-masks-effective-at-filtering-airborne-viruses/979683.md?page=3)