When HN users recommended it
1 HN user recommended this in 2020, in one comment.
20072026
Each tall tick is one HN user's first recommendation. A short tick is the same user again. Click a tick to jump to the comment.
1 HN user recommended this in 2020, in one comment.
Each tall tick is one HN user's first recommendation. A short tick is the same user again. Click a tick to jump to the comment.
The primary purpose of a filtering mask [is to protect the wearer][0]. They coincidentally protect the environment, too, [unless of course they have a built-in check valve][1] that passes unfiltered air out of the mask.
[0]:https://ohsonline.com/articles/2014/05/01/comparison-respira... [1]:https://www.amazon.com/gp/product/B008MCV1HY/ref=as_li_tl?ie...