My understanding is that most masks work better because they prevent you from exhaling the virus which other people can inhale. Which would work fine if everyone wears them, but not everyone does. I vaguely recall a study which said you need 70% or so of people to wear a mask to slow viral spread, and if numbers were below 40% it was pretty much ineffective.
To actually prevent you from inhaling the virus you need an N95 mask or better. But those are being directed at front line medical workers, which is fine.
So can regular people buy masks that’ll prevent you from inhaling the virus nowadays? Are there any masks a regular person can buy that’ll prevent them from inhaling the virus, rather than just prevent them from exhaling it into the environment?
My understanding is the virus is about 100nm in diameter, but it is usually attached to mucus or spittle droplets. So if a mask can block those droplets it should block the virus too I’d assume.
I did have some dust masks that filter down to 1 micron, I don’t know if that is enough to prevent the inhalation of spittle droplets with viral particles on it.
As I understand it, there are two main aspects to whether the mask will do what you are asking, and then a third thing that is also crucial – wearing it properly, which I won’t address here.
The first 2 things are (1) the filtration capability of the mask material, and (2) the seal made by the mask around your face.
A surgical mask has sufficient filtration, but not a sufficient seal. A cloth mask might be made to seal well, but not have sufficient filtration capability.
The best thing I’ve seen for making something like an N95-equivalent mask is to use a surgical mask with a mask brace that makes it seal properly: https://www.fixthemask.com/. Designed by former Apple engineers, they have begun the process of getting the necessary certifications in the US. The design can be done with 3 rubber bands, or mass produced from sheet rubber, and it is open source – available to anyone under open source licensing.
Other options are getting actual N95 masks, like from eBay, if you take a chance and are willing to pay many times the usual price.
There are KN95 masks widely listed for sale. It’s a Chinese certification similar to N95. If you can get legitimate ones, these should also fit the bill.
Finally, there is research being done concerning diy mask materials, and layering different materials might provide enough filtration. But I don’t think there have been enough studies to know for sure yet.
I don’t know what’s available right now, but you’d be looking for a respirator, not a mask. Something like this.
They make a seal against your face and filter the incoming air. They do have a valve, so anything you exhale isn’t filtered. These are designed to protect the wearer. This is the type of mask you’d see someone wearing when welding or spray painting or sanding or making meth.
In the case of 3M half masks (and probably the full face ones as well), you buy the filters separately so you can pick the ones that will work for what you’re doing and replace them regularly.
As for which filter to pick, anything is going to be better than nothing, but I don’t think 3M is making recommendations on which one, if any, will filter out the virus particulates.
You do not need to wear a half piece respirator. N95 masks are also respirators. And they are made to seal sufficiently, if you get one that fits properly. In healthcare settings they test this by, among other things, having a person put on the respirator and then releasing a sweet or bitter smelling agent. If the person can smell it, they fail the fit test with that model of mask.
This is not exactly correct. You can still in inhale virus through an N95, but the chance is small. Many materials will have some filtration ability against small particles, but different materials offer different filtration abilities. A surgical mask can offer N95-like performance, but it requires getting a good seal around the edges. Cloth masks made with good fabrics offer reasonable filtering ability, but their fit is often poor which lowers their performance. You can also get better performance by layering fabrics. Here is a chart about how well different fabrics filter .02-micron particles, which are 5x smaller than coronavirus:
There is more info at the website about different materials and how much improvement you can get by adding layers:
And here’s a place which is selling surgical and KN-95 masks:
Around here (Brooklyn, NY) KN-95 masks are easilly available. I’ve been wearing them all the time, whenever I leave my apartment, rather than the more comfortable surgical masks, because of the ridiculous number of people who can’t be bothered to wear any kind of mask.
I made N95 equivalent masks by 3d printing the ‘montana mask’ designed by a clinic, and then you insert your own filter material.
One filter material often overlooked is a high-filtration furnace filter. MERV-13 furnace filters can block particles as small as 1 micron. I bought one and ripped it apart, and it had enough material to make lots of filter inserts. You can’t make a complete mask out of it, as it’s not designed for strength But as an insert between two layers of cloth, it’s great.
I got these masks from amazon. https://smile.amazon.com/gp/product/B08923JK7H/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
I didn’t know I was getting KN-95 masks, because the listing does not specifically say that’s what they are. But the box has KN-95 on it and so does each mask. A box of five is $16.24, and I got two boxes. I reuse them. I leave a used one up on the dashboard of my car in the sun for at least a day. The outside temp is up to almost 100 every day. The temp inside the car is probably 125-140. I once got a thermometer to measure the temp inside the car in the summer, but it melted.
One way to get a better seal with the KN95 masks is to fold inward the thin seam along the edge of the mask. When I wear mine, I can feel a lot of unfiltered air moving along my nose and cheeks and my glasses get fogged up. By folding the top and side seam to the inside, I get a much better seal and it feels like no air is escaping through the edges. I also clip the loops behind my head since otherwise it doesn’t fit tightly enough to my face when it’s just around my ears.
I’d be surprised if that would be high enough of a temp to kill the virus and your windshield is going to block enough UV to prevent that from disinfecting it.
Enveloped viruses aren’t as hard to inactivate as those with just a capsid. If you’re just decontaminating from going to the store, I think leaving your mask in your car for a day will do fine.
I’ve seen temperatures of 140-158oF of dry heat for 30 minutes being tested. Of course your oven doesn’t go that low so you may be able to just let your mask go in the preheat then turn it off at 170 and let it slowly go to room temperature.
I get a good seal with surgical masks by stapling in another pleat on the side gaps to fit my face. I know it seals better because when I inhale and exhale, the fabric sucks in and out against my nose instead of escaping out the sides. My glasses don’t fog up, either.
I believe the “holes” are actually the areas of the mask which are fused front-to-back. It’s those little rows of squares you can see in the picture. I have some similar masks and it’s like a melted area that is solid. It it somewhat transparent, but that’s probably because of the heat fusing melted those squares and the solid plastic is transparent.
But that being said, anyone can print anything on a box, as I learned from the movie “Tommy Boy”. The masks from China don’t necessarily have any quality control or oversight. They may meet KN95 standards, but it’s hard to know for sure without testing them.
Really? Not even remotely close to true. In fact, after walking around the grocery store for a while, I have to go off in a corner and lift the bottom of the mask for a nanosecond to get some air.
