Wearing a mask...any health risks?

But you already had them in your system to begin with. You'll only be contaminating yourself with bacteria or viruses you already have. The moisture does provide a possible breeding ground for outside bacteria, but that's why you're supposed to change the mask at least daily.

Now, if you borrowed somebody else's mask that they've been wearing there is a potential problem.

CO2 is molecular size and masks are not going to block the flow of CO2 or oxygen back-and-forth through the material. They're esigned to minimize the passage of microscopic size entities like bacteria or viruses, but I'm not completely sold about how effective they are for that, either...........................Luca

Valid point, RSM. Your body does try to rid itself noxious entities with coughs, sneezes, emesis, diarrhea and emesis.

I'm no authority on the topic but bear in mind that:

1). Our oral and nasal cavities are already filled with bacteria and probably viruses. When we cough we do expel them but they were already present within us and have achieved an equilibrium. We don't bother them and they don't bother us. We have a jungle of staph epidermidis, non-pathogenic strep, anaerobes, and countless microscopic monsters in those cavities but we keep them at bay with our immune system. And those areas are relatively sterile oases compared to the colon.

As an example, when we're trying to demonstrate our manly manliness as college freshman, drink too much and spend the night heaving into a gutter - not that such an experience would be familiar to you, of course - it's not the vomiting that gets rid of the alcohol. Our body eradicates it by metabolizing it, with the byproducts being exhaled and passing through the kidneys.

2). I'm not so sure that when you sneeze into a mask that anything is forced back. Air is pushed out laterally and inferiorly around the mask but I wouldn't think a significant risk is posed by pathogens getting "forced back in."

3). At any rate, it's not these expulsions that are our primary protection against infection. It's our immune system which allows a communal relationship with trillions of non-pathogens but is extraordinarily efficient at destroying the pathogenic varieties. If all we had were coughing and sneezing, we'd all be dead of pneumonia before we were one month out of the womb.

But I'm still not going to wear a mask unless I'm seeing somebody who is overtly ill. Ridiculously long response to a simple question. Sorry......................Luca