I never said masks make things worse (with the exception of the doctor) - I think I said the opposite.

My doctor should wear something that has a filter capable of catching the virus, such as FFP3 respirator. When you breathe in, droplets get through the mask (this gets progressively worse as the mask gets wet) - and if the mask is not a FFP3, you're making a bet that none of the droplets that get through are contaminated, because the mask does not protect you from the virus, it merely protects you from some of the droplets around you; only the correct filter will protect you. The virus is around 50-100 nanometers.

It's probabilistic, like everything, but N-95 masks do protect the wearer from particles that small. The CDC purposefully lied to you so that you wouldn't stockpile masks they (understandably) wanted to use elsewhere.

/https://www.semanticscholar.org/paper/Filtration-Performance...

>Consistent with single-fiber filtration theory, N95 and P100 respirators challenged with silver monodisperse particles showed a decrease in percentage penetration with a decrease in particle diameter down to 4 nm.

If the mask stops some droplets (which it obviously does, as it gets wet over time) and some of those droplets carry the virus, then obviously the mask protects against the virus - not 100%, but some percent (just like condoms!).

Nope. It protects you from said droplets, not from the virus, which it is incapable to protect you from, unlike a FFP3.

But as far as we know, the bare virus does not travel through the air, it only travels in droplets. Although there is some disagreement on how large those droplets are.

I feel like I have a wrong model of how things work.

I'm thinking that for each virus there is a chance that it will infect a cell. The higher the viral load, the higher the number of chances that you will get infected.

a lower number of droplets -> lower viral load -> less chance to be infected.

What is the physical explanation behind this fact, and how come normal masks protect others if a carrier wears it?

The physical explanation is simple, the gaps between the strings of the mask are significantly wider than 50-100 nm. The mask protects others through preventing you from breathing/coughing on them, which it does way better than preventing you from breathing contaminated particles in.

so you're saying that the gaps are so wide that almost no contaminated particle (getting in) will get stuck on the mask?

but somehow (some of the) particles going out will get stuck.

how is that simple?

if masks don't make things worse, then they can only help.

(to explain more: there is a mechanism by which they help. so for them to not help (in total) , there must be a way in which they make things worse)