That article is kind of (OK, a lot) overblown. It makes it sound like wearing an N95 with an exhalation valve is no different than not wearing a mask at all. The exhalation valves won't be found on medical grade N95 masks, but you do find them on masks used for construction, painting, sanding, mowing the lawn, etc. But do keep in mind that OSHA and the CDC have recommended N95 masks with the exhalation valves to be used in hospitals while treating COVID-19.I was reading an article the other day where it was showing what a N95 mask with an exhaust valve looks like and that is the worst kind of mask you can wear in this situation. They are saying we should wear masks not to protect ourselves, but to protect everyone else from us and the exhaust valve renders it useless in that situtaion.
You wouldn't want to use a valved mask (or a standard surgical mask, for that matter) where a sterile field must be maintained (e.g., during an invasive procedure in an operating or procedure room) because the exhalation valve allows unfiltered exhaled air to escape into the sterile field, just as the non-sealed standard surgical mask or homemade mask or scarf would.
The article attempted to make the reader believe that a homemade mask or something like a bandana will somehow magically prevent the virus from being exhaled into the atmosphere, yet an N95 mask with an exhalation valve will somehow just spew the virus everywhere.
If you wear a standard surgical mask, most any mask with earloops (instead of headbands that pull the mask tight on the face), any mask that doesn't have a tight seal on the face, that allows air to enter or escape through any opening, any mask that will allow your glasses to fog, it's just as useless (or just as effective) as an N95 mask with an exhalation valve at protecting others.
A homemade mask, scarf, bandana, surgical mask, etc., and an N95 with an exhalation valve, all offer exactly the same protection to others, in that it dramatically reduces the distance and spread of exhaled virus.
The only difference is, an N95 mask with an exhalation valve ALSO protects the wearer, and keeps the heat and moisture level inside the mask to a manageable level. But one with the valve is no better or worse at protecting the people around the wearer than is any other non-sealed mask.
Whether you're wearing a mask with a valve or any other non-sealed mask, you don't want to lean in a foot away and have a lengthy conversation. You still want to maintain your distance. But the notion that an N95 mask with a valve is useless, compared to a surgical mask or homemade mask, is absurd.