On 27/01/2021 12:25, David wrote:

The vented models don't protect anyone else.

I don't agree. For two reasons:

1. There's a bit of a labyrinth for exhaled breath to pass through the
valve, and this will stop quite a lot of the droplets. In a cold room,
my masks leave a little condensate trail around the place!

In any case, unless extraordinarily well fitting, with very tight
straps, a lot of the exhaled breath from unvalved masks comes out round
the edge.

2. If you protect yourself really well, then you're a lot less likely to
be spreading virus in the first place.