el gato wrote:
sametime wrote:
I spoke to an infectious disease expert about the use of the filter/mask. He thought it would be as effective as the n95.
I just can't see how this is the case. In a former life I used to be a member of our company's volunteer emergency response team. There were quite a few hazardous chemicals in the labs, and the local FD really had no idea or interest in properly dealing with spills of these chemicals, so we were the first line of defense in an accident. We used to practice and certify quartely on the use of PPE, up to and including SCBA gear and full hazmat suits. One of the things we had to do was an annual fit test for whatever PPE we were certified to use. That involved wearing a mask and doing various things like talking, exercising, etc. while they measured for leaks around the mask seal. It's pretty eye-opening to see how little it takes to get one of those masks to leak if it's not propery fitted and you're not careful and clean-shaven. It doesn't take much of some of those chemicals to have a really bad day.
My understanding is that N95 masks require a similar (though admittedly less rigorous) fit test to ensure they fit each individual properly. I just can't see how Emilio's (or anyone else's) sewn fabric mask, with or without a HEPA filter, can achieve a good enough seal to be equivalent to a properly fit N95 mask. Now, that's not to say that Emilio's masks are no good- I've ordered a bunch for our family and extended family and they're arriving today. But, it would be a HUGE mistake IMO to assume you have N95-like protection with these masks by adding some HEPA material to them.
Similar to you, I, too am a bit sceptical about that claim. At least some N95 respirators operate on more than principle of size exclusion, and these respirators contain fibers having electrical charges (aka electret fibers), and these electret fibers also help with the filtering. Conversion of regular polymeric fibers into polymeric fibers bearing static charges is far from trivial.
That said, similar to you, I've also ordered a few mask from De Soto, as the masks would fill in for occasions when we aren't around too many other people (e.g. taking a walk or perhaps even a bike ride).