Masks Don’t Work:A Review of Science Relevant to COVID-19 Social Policy

Even those who tought the efficacy of wearing a mask can't agree on what kind of mask to wear, so if you really want to be protected, you should don a Level-B HAZMAT suit with SCBA in a "clean" environment, and undergo a full decontamination before reentering the "clean" environment.

Thank yo for the medical share sir.

The only thing a mask does is make you breathe back in your own carbon dioxide, which is really not good for you.