Maybe a model in between? Because while source control masks are droplet traps I think the spitting model may be over simplified.
Normally we are talking about smaller airborne droplets rather than intentional spitting of very large droplets, small droplets that are not intentionally expelled and are carried out with the air of our exhalation, so I’m thinking a lot of those will go with the air on the path of least resistance.
Not saying that nobody should use filter inserts, mind you, but rather I think that they may give many people a false sense of efficacy when they buy and use an insert that says 2.5 microns (as are sold all over the place) and think they suddenly have a respirator-grade mask instead of just a cloth source control mask. So I’m interested in finding out more and I’d love to see data one way or another.
Yah, I think the truth is that we’re still figuring a lot of this out. It was only recently that we had enough data to say with confidence that homemade masks are worthwhile.
At some point we’re optimizing into a local maximum, I guess. We can’t get Americans to wear any masks at all, so maybe debating the finer points of filtration is a whole lot of navel gazing at this point.
It’s variable according to that link. Time of day, and local cloud cover matter too. It’s also a terrible UV source, My classmates and I tried erasing EPROMs and it took 2 days before we could verify every chip we tested was erased.
I’m not using an N95 mask. And my mask is also made of (mostly) paper.
The reason medical personal wouldn’t want to use plastic bags on a large scale probably has more to do with keeping the person responsible for cleaning and storing the masks safe.
It’s a time thing. It’s a difference of hours. As I mentioned before. Viruses that have a similar envelope structure tend to have similar viability outside of a host.
A lipid envelope virus like coronavirus, herpes, chickenpox, or influenza can be pretty fragile outside of a host, although inside the host that envelope is to their advantage and helps them last a very long time in a host (some can last indefinitely really). Can be a few hours to several days, that sort of range is what epidemiologists have been trying to narrow in on for COVID-19. Soap is really effective on lipid envelopes. So wash your hands before touching your face, mouth, nose, or eyes.
A non-envelope virus like norovirus or poliovirus can last for many months on a surface. It’s a little rolled up protein (capsid) that has to in in contact with the right place to work, it just kind of rattles around like a lottery ball and it gets a big pay off. Many of these kind can cause an infection from a single particle. They’re scary stuff, and if our pandemic was something like polio or a fatal norovirus, we would be in a lot of trouble.
I don’t think we realized just how poorly prepared we were for pandemics. We’re lucky so far in not having something super terrible.
