Polyurethane plant fire - GIF

[mccwho]

""A mask rated 95 will stop 95 percent of airborne particles that are 0.3 microns in size and larger, while a mask rated 100 will filter out 99.97 percent of particles 0.3 microns and larger, making it comparable to a HEPA (high-efficiency particulate air) filter. (The average human hair is 70 micrometers in diameter.)

Activated carbon vs. chemical agents

Paper-filter masks, however, are useless against most chemicals, whether paint fumes, sarin gas or airborne organophosphates. Those threats require a mask with activated carbon, also known as activated charcoal.

Charcoal bonds with the active ingredients in nerve gas and other chemical threats, effectively filtering those toxic compounds out of the air inhaled by the mask's wearer. As long as there's space on the charcoal filter's fibers for incoming toxins, the wearer is safe.

But after a period of time — depending on the density of toxic chemicals in the air, the wearer's rate of breathing and other factors — an activated charcoal filter will stop working and will need to be replaced. Most activated charcoal masks have disposable filters that are easily replaced. [End of the World? Top Doomsday Fears]

There are other limits to the effectiveness of these masks: They don't always provide eye protection, and any mask is only as good as the seal around the wearer's face — a leak or a weak seal would render them useless.

That's why many professionals, including hazmat teams and emergency first-responders, wear full-face masks that are connected to an air supply, such as a small air canister or a scuba-style air tank.""
https://www.livescience.com/39217-ho...asks-work.html

Exactly, you're spot on correct!

I laughed so hard when they said we should wear cloth mask and before that (and again now) the N95/N100 mask I'm still laughing at them!
IF any of those masks were effective against an airborne virus than that is what they would wear in a L4 lab. Guess what, they wear something completely different in a L4 lab that is dealing with airborne viruses . I still remember my medical training from 68W & 18D courses in the Army. N905/N100 mask are meant to prevent infections from bacteria and to protect patients. The Army uses NBC suits when dealing with viruses. HAving said that its always good measure to have a current NBC rates mask filter around.

Most viruses vary in diameter from 20 nanometres (nm; 0.0000008 inch) to 250–400 nm; the largest, however, measure about 500 nm in diameter and are about 700–1,000 nm in length.

1 nanometer = 0.001 micrometer (micron)
Wearing a N95/N100 and thinking your going to stop a virus is like trying to catch a needle with a net that has holes in it the size of a football stadium. (Not literally but you get the idea).