a collection of viruses on the outside surface of the mask collected at the end of the day (along with many other particles)? So if you're wearing the mask, then taking it off, couldn't viruses still be spread by touching the surface of the mask or having it lying around afterward? If you have a legitimate mask that is single use and disposed of each wearing, it wouldn't be an issue so much, but I'd guess most people are reusing masks repeatedly. The net result is undoubtedly still a reduction of contact, but a virus in the air that you don't otherwise breath in has to go somewhere.