BTW, the N95 standard means the mask itself removes at least 95 percent of 0.3 micron particles at test conditions. That particle size is the most difficult to remove (explanation is beyond the scope of this posting).
Only IF you wear it properly. I have to take a FIT test every year...for the N-95 masks....
Most important lie that anyone had to make on quite a while. He did the right thing to save the lives of our medical staff.
Nope. it was the truth then and it is the truth now
Making your own mask? Researchers say some fabrics can filter nearly as well as an N95.
A new study from researchers at the University of Chicago says that a combination of cotton with silk, chiffon, or flannel can create a well-functioning filter.
“We found that many common fabrics can be surprisingly good at filtering particles,” said Supratik Guha, a University of Chicago professor and author of the study, which was published Friday in the journal Nano.
However,...If your mask leaks around the edges, unlike the tightly fitted N95, your homemade filter will lose its effectiveness.
Tighter-woven cotton alone was found to be effective, particularly two layers of 600 thread-per-inch cotton. So was a cotton quilt made of two 120 thread-per-inch cotton sheets, with a 0.5-centimeter batting of cotton, polyester and other fibers. Four layers of silk — imagine someone bundled up in a scarf — also performed well.
But the best overall filtration was provided by a sandwich consisting of one layer of the tighter-woven cotton plus two layers of silk, or two layers of chiffon, or one layer of flannel — because of the electrostatic filter created by the non-cotton layers.
0.3 microns = 300 nanometers. Size of COVID = 200 nanometers?