The mask, which fits tightly over the nose and mouth, is supposed to filter out at least 95% of small airborne particles. Although they don't require a prescription, N95 respirators must be properly fitted to each person if they were to be used in the workplace by healthcare workers, for example. FDA requires that companies marketing these kinds of devices during health emergencies must ensure they are certified by the NIOSH to provide the proper filtration without hampering a person's ability to breathe. According to the FDA release, the agency will be issuing a guidance document about this kind of device soon.In related news, a recent article in the Star Tribune notes that the verdict is still out on whether or not face masks will protect people during a "super-flu." However, aside from the general "wash your hands" rule, the Centers for Disease Control does recommend using a N95 respirator when caring for a sick person.Unfortunately, we might never know just how effective these devices are until a disaster strikes.