How are N95 masks effective if 5% doesn’t get filtered and passes through?


To me I just don’t see how this would work or filter anything. So it 95% is blocked, then 5% of the particulate will pass through the filter and cause harm. It’s like saying you are on a submarine and saying it’s 95% sealed. Then the rest would fill up the submarine then you’d end up dead. Is there something else I’m missing here?

In: 0

They’re good, not perfect. 5% is a lot less than the ~60% of droplets that get through regular surgical masks.

Part of their efficacy comes from their tightness to the face. Unlike regular surgical masks ideally there will not be any air passing by the mask’s edges.

Not to mention the store bought cloth masks which are even worse.

N95s are designed to protect the wearer from exposure to pathogens.
Surgical masks are designed to protect others from the wearer’s pathogens.

Viral load matters. although we’re still not 100% sure why one person gets infected while another one may not, we have definitively proved that inhaling 100% of the virus particles is way way way more likely to cause a disease than inhaling 5% of them.

Your submarine metaphor would make sense if you added in that the submarine has a bailing system that can tolerate leaks and stop them from getting worse.

If you were going to be sprayed in the face with poison, would you prefer a full dose of poison or only 5% of the full dose?

Just because it’s not a complete solution doesn’t mean it’s worthless. The same way that helmets and seat belts decrease the chance of severe injury or death on bikes and in cars, but don’t make you invulnerable.

> It’s like saying you are on a submarine and saying it’s 95% sealed.

No, it’s not like saying that at all.

It’s more like saying 95% of the UV rays are blocked by the sunscreen. Not 100%, but still substantially reduces your chances of getting skin cancer.

Think of every droplet that you breathe in as a little roll of the dice for how likely you are to get infected. If your goal is to not get infected, you want to roll those dice as few times as possible.

This happens in both directions: if you are infected without realizing it (everyone typically is 1-3 days at the start of their infection), the mask also reduces the number of dice rolls the people around you have to make, even if they aren’t wearing a mask.

Fewer dice rolls in a community means a lower rate of infection in the community, allowing the hospitals to keep up and allowing people more time to get vaccinated or boosted so that if they do get infected, they’ll almost be guaranteed to survive.