A face mask that does not cover the nose is equivalent to no mask.

Pretty sure it's the nostrils that matter. The grandparent post was talking about needing your nose to be partially visible—and the top half of your nose is just skin.

How do you accomplish a tight fit that seals of though to prevent air from going out at the top without covering your nose completely?

I think it differs for everyone, but I can only get a good seal by having the top of the mask (with the bendy metal bit) well down my nose, so the metal bends down into the "crease" bit on the outside of my nostrils. If I have it higher near the bridge, inevitably air comes up my cheeks and out to fog my glasses. My nose is fairly big, I suppose.

Oh, I've been wearing my mask wrong... My glasses fog up as well, and I've been putting my mask at almost the same height as the lower frame of my glasses...

Realistically, with cheap masks you really can’t. I tried all the “life hacks” suggested and none of them work, some fogging inevitably happens.

The only way is to get a proper N95 or N99 mask, which has padded edges that make for a proper seal. You’ll also be safer.

Literally impossible if you have a big nose.

Your mask still covers your nose, just not the whole nose. I'd say covering your nose up to 80% works fine.

Maybe it's useless for not getting virus, but it works not to spread virus while talking.

Interesting idea, though I’m not sure this is a good idea. Exposing one’s nose defeats the purpose of wearing the mask.

As an aside, I’m super curious to see whether Face ID works with the transparent PurME masks.

https://www.indiegogo.com/projects/purme-a-gas-mask-you-can-...